on the topic. Very excited about this stuff. So please go ahead, Arjo. So thank you, Mark. Hello, everyone. Today, I'm Arjo from Open Robotics. And I'm going to be talking about maritime robotic simulation and focusing on some challenges, perspectives, and some new features we've added to our simulation platform, Gazebo. So a bit more about us. We are a company based out of Silicon Valley. We were originally the Open Source Robotics Foundation. It's a privately-held company with 50 employees.  We had founders and key contributors to some of the world's most widely used robot software, including ROS, Gazebo, and now we have the OpenRMS. So this is sort of our product range. I guess I'm introducing a company because we'll be having, I think, two others in these sessions. And then there'll be Catherine later on from our company discussing open ethics. So yeah. So without further ado, I'm going to dive into the agenda. So I work, as I said, I work on Gazebo, which is the simulation platform that we have. So today, I'm going to introduce Gazebo. I think many of you who work in robotics would probably have no idea of it. And then you can run. I'm going to be working with that. And then we'll be discussing what makes maritime robotics different, because this talk is about maritime robotics. We're going to talk about some recent developments in Gazebo SIM that support this. And finally, we're going to talk about using a case study where we actually use Gazebo to simulate a real-life robot from a built by Monterey Bay, a aquarium research institute. It's a long-range underwater vehicle that is used for science sampling missions in the Pacific Ocean. So a bit about Gazebo. So Gazebo started out in University of Southern California. It was a project there. And then eventually it was adopted by Willow Garage for integration with Ross. And we've been using. Then open robotics took over the development of Gazebo in 2012. So around 2019, we felt that it's about time that Gazebo has a rewrite. And so we've started as a refactor, but eventually turned out to be quite a different monster. And so now we created the ignition Gazebo, which right now we're in the middle of a rebrand. So we are going back to client Gazebo SIM. So you can see on the top left-hand corner over here this is a screenshot of old Gazebo. And the new Gazebo on the bottom right-hand corner with a lot of new features, including softable physics engines, rendering engines, and much more extensibility. So with that aside, I'm going to talk a bit about maritime robotics first. So maritime robotics refers to underwater and surface vehicles. My talk will be mostly focused on underwater. But a lot of the stuff that works for underwater also can be translated to surface. So a few things that make it different. The physics is different, right? So we have things like ocean currents. You have to account for things like buoyancy, which is what the hydrostatic is about. Hydrodynamics, which involves how the vehicle moves. Environmental currents. So like, as I mentioned, ocean currents, wind, waves, things like lift, drag. These are things that, well, lift is something that aerial robotics care about. We don't really see any ground robotics so much. And they make simulating this a bit more. The physics is a bit different from what you would need to simulate for a real ground-based robot. Apart from that, we have issues with communications in the maritime world. So if you're underwater, water will block the radio waves. And so you can't sit and use Wi-Fi or traditional 4G networks underwater. You have to use other systems. So often we resort to acoustics, optical communication, or tethered communication. Acoustics being using sound. Optical being using light. And tethered being using a wire, which obviously has some issues with range and how things can move. The other challenge is localization underwater. So no radio means no GPS. You will not have very good static features, like in the pitch on the right hand side, like underwater, you've got plants and animals, which don't make very good static features. Sometimes the water quality is very, very poor. So we have to resort to other techniques. Some of these include using things like Doppler velocity. We'll talk about a bit more in a moment. And acoustic transponders, which, again, I mentioned before, acoustics is a huge part of maritime simulation. So I'm going to keep saying acoustics over and over again throughout this talk. Then there are perceptions. The sensors we use also are different underwater. So you've got things like imaging sonars, which are kind of, think of it like a medical, the image you get is something similar to medical ultrasound, where you have this fuzzy image. You can see in the, this is the photo you see on the top right here is an imaging sonar photo. You've got Doppler velocity logs, which is this thing down here. This is actually used for positioning of echo. It uses a sound wave. It emits a sound wave and waits for an echo. And when it receives the echo, it measures the amount of Doppler shift there is, which is the frequency shift, which tells you how quickly you are moving. So that together with the depth information can sort of help you localize. And that's inertial memory units. The traditional sensors like cameras and LiDARs also exist, but cameras often have very poor visibility underwater with few features and underwater LiDARs, while they exist are very, very, very expensive. I mean, imaging sonars themselves are very expensive, but underwater LiDARs sonars are more expensive than that. So these are some perception sandwiches. Environmentally, unlike your traditional robotic simulators, where we are looking at mostly two 2.5D terrain, we're looking at a very three-dimensional dynamic terrain. So here you can see some screenshots from our software where we are visualizing data. This is science data that is provided by the Monterrey Bay Institute Research Institute. So for instance, things like temperature, salinity, and why do we really care about these? Well, one is of course this customer that I'm gonna talk about later on cares about environmental, they do a lot of research in the environmental conditions and ecology, but apart from ecology and stuff, we actually need to know all this stuff because things like the speed of sound change with temperature, then knowing ocean temperatures also helps predict in their flow, whether there's a lot of reasons why we need this information. There's also the fact that the world is round. So most of our robot simulators, including Gazebo, assume that the world is flat and I mean, we do live in a flat world. If anyone tells you otherwise, they're lying, but apparently the maritime world believes the world is round. So yeah, we'll be going for, we have to count for the roundness of the world in our simulation and apply the appropriate distortions to the data we have. So the thing is underwater simulation is actually a big field because underwater robotics is actually quite commonly used in the industry where we are seeing oil and gas, sign, mayvies and many other people using underwater robots for exploration, for maintenance work, for lane cables, for repair work underwater in our infrastructure like oil rigs. So there is actually a huge drive for this and hence there's actually quite a few simulators built for underwater robotics. And this is just a small selection of simulators that are more prominent in the community. So one of them is the UUV simulator, which was based off the Gazebo 9, I think. Project Dave, which Fox UUV simulator actually is also partially maintained by us and the group at Naval Postgraduate School in the U.S. Its focus is more on manipulation, but there's others like UWSim, Virtual Robot X. Again, these are all, so UWSim uses its own engine, but Virtual Robot X is also based off Gazebo. Now, the latest trend is that we're bringing a lot of these features into our main line Gazebo sim. So you don't need to rely on other repos, you know, downloading extra software just to support this use case. So Gazebo sim, as I mentioned, is our rewrite of the old Gazebo. So a lot of things have had to be rewritten. So I'll be focusing a lot on Gazebo sim itself, which is, so as I mentioned, this is actually a very active field. The maritime robotics community is growing. We have in the last year added many features to Gazebo and this year is also going to be very exciting. We'll be adding many more and we'll discuss them some more in depth. We've also created a new Ross Maritime Working Group where people who are interested in underwater robotics or surface robotics can come and join and discuss the problems there are. We've had two meetings so far and it's a monthly schedule that we will be following. But let's talk a bit about the recently developed features. So this is a list of recently developed features. It's pretty text heavy, but the idea here is that we've developed quite a few features for the maritime specific. So how do we build an open source? So now I'm gonna transition a bit. So I thought just now about Gazebo sim, right? I'd like to now go into deep dive into a case study where we were actually built using Gazebo to create a digital twin of a real life underwater vehicle. This vehicle in front of you built by Monterey Bay Aquarium Research Institute. It's the Long Range AUV, which is used for serving and science missions. This vehicle uses its own controllers and they're appropriate controllers, but the folks at Monterey Bay Aquarium Research Institute want to hook this controller into a sort of simulated rig. And they chose Gazebo because it's extensible. It'll allow them to iterate quickly and it has support for multi-robot systems. So we can do a lot of very interesting things with it. And obviously the reason they want to simulate this is because testing this is quite expensive. You have to test it in deep ocean. So you have to bring it out to the ocean and drop it in. You have to charter a ship, which can be very expensive, sometimes about hundreds of thousands to millions of dollars just to do a test. And the vehicle itself would also cost and similar orders of magnitudes because of the sensors on board. So they have been using their own simulator, but they felt that it's not as extensible as Gazebo. So they came to us and asked us to build something for them. So we'll be going through some features that we introduced for this. So I'll just introduce this vehicle first. It's a rather interesting vehicle. It's the folks at Monterey Bay write us with this diagram. But basically you've got several systems here that affect the actuation of the robot. You've got a shiftable battery pack which causes the robot to tilt. You've got an emergency drop weight for emergencies you drop that, surfaces. We've got a variable buoyancy system which basically tunes how buoyant the robot is. So the variable buoyancy system is combined with a shiftable battery pack to sort of see, to adjust for maybe inconsistencies in the mass and stuff. Then there's an elevator and rather for controlling the direction and finally a propeller for pushing it forward. We also have a bunch of sensors and these on the diagram, you can see the green and blue dots, the green reference to stuff that was already worked on in the past year, the blue referring to stuff that we're working on right now. So acoustic communications is already in. We're working on a Doppler velocity log which measures the speed at which the vehicle is moving. The rest of this is science sensors mostly which are specific to the Monterey Bay Aquarium Research Institute but a lot of research institutes that are building underwater vehicles have similar sensors that they care about that give data at a certain position. So they might read like, so here you have CTD, which is basically a certainty temperature and density of the thing. There's a fluorometer for measuring chlorophyll but you could also have things like DNA sample. DNA sequence starts placed in the bulkhead. So we need something that can do positional look up. So let's take apart what we have to actually do to simulate this first. So we have this system and so ignition gazebo is same as great because you can extend it using plug-in. So here's an example snippet of what a plug-in, how you bring a plug-in and you just give this XML and you put it in. This slide may look scary but basically we're talking about hydrodynamics here and drag. We are simulating the whole equation. This is called Fawson's equation and I'm not gonna go into the exact details but the basic idea here is that this is what we use to approximate the behavior of water. So it damps how the vehicle is moving. And so we've introduced a plug-in upstream for this work. So you can actually do that. And there are some parameters you have to fill. These normally are engineering parameters which people in the maritime domain are familiar with this. But these are like numbers that describe how the vehicle drag should behave in different orientations. We also added a thruster plug-in so you can just give your propeller diameter, the fluid density and the coefficient which is again something that is an engineering parameter. I just add it as a plug-in. We have also a plug-in for buoyancy. This is a world level plug-in so it doesn't affect all objects in the system. We had a uniform buoyancy plug-in for quite some time but we also introduced what is known as a graded buoyancy for systems like the ocean where you have an ocean interface between above the ocean is air so you don't have much fluid density like air has a density of about one kg per meter cube. And below it is water so that's about 1,000 kg per meter cube. And you can even do multiple layers and that's kind of useful for maritime use case where for instance the density of water actually changes as you go up and down with certainty and temperature. So having separate densities can be a useful trait for various groups. So buoyancy actually is probably the most important force here because it creates what's called a writing moment and this is what makes your vehicle stable. So based on where your center of buoyancy which is where the center of volume is and the center of gravity these should be at two different spots. So for an underwater vehicle the buoyancy should be above the gravity and so it says V above G and this creates like a turning moment. So if you push the vehicle to one side it will restore itself up straight. If you have it the opposite way it will create a lot of oscillations and your vehicle will be very unstable. It'll capsize and you know. So this is something that actually we needed to simulate. And for most systems it's pretty simple because like you have a fixed object that's all but in ours it's a bit annoying because one is the center of gravity can be shifted by the shiftable mass factory crack and the variable buoyancy system can also adjust the buoyancy of the system. So in order to solve this problem small errors, you know like the mass distribution is super important and you know we are given a diagram like this. We don't actually have the accurate measurements for volumes and CAD data that we need. For instance this front head actually gets flooded with water which means that even though in the CAD it is say like 12 kg in real life when it's submerged it could be something like 30 kg. We don't have the data of how much water comes in. So we actually have to sort of that calculate things. So we have to sort of automate this process. We created this model and tool which sort of takes in the properties of the vehicle, the certain offsets we need and the fluid density and calculates the desired buoyancy parameters that we want. This might seem like a bit strange but it is necessary to make sure that the vehicle is controllable. And keep it, this simulation actually is supposed to run at 100 times real time speed. So small errors will look very amplified in the system. So we had to automate this and build it up. But the question now is okay, we've built the system with different plugins, different buoyancy systems. So how do we actually validate this physics behavior? So we want to have simulation in the loop. So basically that's the controller that's running, which is Mabari's controller and then there's Gazebo running, right? And the controller should believe that it is living on its own vehicle and there shouldn't be too much change between the controller and the real vehicle. So all the changes is the interfacing the drivers that interface with electronics versus the drivers that interface with Gazebo. So we want to do this and the thing is the physics fidelity should be good enough to control that the control system can be used in the simulator and in real life. So one of the issues was validating this. So we actually came up with a test strategy. We needed, we had unit test integration tests. So unit test being vehicle, simple things like if the thruster turns on, the vehicle should move forward or if the mass shifter is, the mass moves, the vehicle should pitch. This is done independent without the controller. And then we have integration tests, which do the same things, but with the controller. This is to debug any like issues that we have in terms of things like sign convention units, because two different teams actually function to that might not communicate very well where you have like them saying that, okay, forward is in on the X axis and we're like forward is on the, well for us it was actually the Z axis is split. And they were using any convention and we were using E and U convention, which is East North up and North East out. So this can lead to a lot of confusion, which is why we have these two tests in place. And then the thing is testing the stuff is, it was initially quite hard, but we actually did not something called test fixtures in ignition that actually makes it easy to write tests. So for instance, for it. So now you can write a unit test very simply for your robot or your system, and anything as using what we call test fixtures. And here you can see example of the API. So you just tell the test fixture that you have this SDF file, which sort of is what your robot description is. And the world description comes from the SDF.  And here you can actually do things like, oh, what is my current velocity? What is the current acceleration? These are things you can query in the post update step. And then you can finalize it. So for instance, like for the master theory, we would test like, okay, what is my pitch right now? Am I pitch too much? Am I, is my pitch stable? Am I oscillating like crazy? Am I doing something funny, like an injector pole? This is used to validate the accuracy of the system. Finally, you have this fixture.server that run, that just says that, okay, let's run the test. And you can have assertions throughout the thing. The really cool thing is that we can load this up and it can be run headless in GitHub actions. So whenever we make a change to our simulator, every, all the physics gets tested against their controllers and we validate that the simulator is actually working or not.  But this has been a huge time saver and has been very useful in helping us debug issues, integration issues. Now I've talked specifically about the one robot, but they're really interested in using many of these robots to do coordinated missions. So they actually have, maybe they will deploy up, sometimes up to 20 robots to do coordinated missions where they search different areas, talk to each other, coordinate behaviors, and they might even want to introduce different types of robots in the simulator. So we actually developed an acoustic communication simulator that builds on top of the Xevo. Unlike traditional wireless comms, the acoustics to communications, one thing to note is your acoustics is very slow. Very low bandwidth. So you can expect only limited by the speed of sound. So unlike, like, you know, radio waves which travel at the speed of light, acoustics takes time. So if I am located 100 meters, it can take up to a few milliseconds to actually get the data across, even just like because of physical limitations. And it can get a lot of seconds of looking at kilometer scale worlds, which is what these guys work with at Mabari. So that is a problem. So we need to simulate that. The other thing about acoustics is thanks to the slow speed, there is a flip side, which is we can use it for localization. And by that, I mean, we can measure the time of flight between two sensors. So here is a simple diagram of how this works. So robot, let's say the robot A is on the tag timestamp, the TSP. It transmits data at TSP. The robot, the other robot receives it at TRP. It responds, it takes some time to respond TSR and it sends TRR. So you can actually guess the time of flight using such an equation as shown above. This is an example of what is called two-way ranging. It is also used nowadays in UWB in other places, but it's been used in maritime for a very long time. So we need to build something like this. Apart from that, acoustic models can be different for different systems, right? You could, so we might only want to simulate very simple behaviors with where direct line of sight happens, but there might be researchers who are actually interested in things like, what if I have a very rocky terrain and the acoustics echoes, then there'd be multipath reflections. So we developed a very simple model, which is direct line of sight, but we also developed the infrastructure that allows this model to be loaded separately. And currently, I think this is going to land by the end of the week upstream in Kazibo. We'll be doing that.   Sorry to interrupt you, but I think we lost your video. So if you can reassure your video feed, that'll be great. I mean, the screen, the slides are there, but just the camera. Okay, give me a moment. Thanks. Interesting. Can you see me? Yeah. Yeah, that works, thanks. All right, all right, sorry about that. All right, so I'm back, coming back to acoustic. So here we're actually using the real life quote that runs on this real robot and we've loaded it up in the simulator. It's hooked to our simulator and there'll be two robots here. So we're going to spawn two robots. One, this first one, and then the second one. This first one is going to, the second one is supposed to circle the first one, I think. So yeah, so the second one will start circling this first one and this first one is going to move and you'll notice the second one will adjust its circling around this first one. So this is a common behavior they use for studying, studying the sort of the different layers of the ocean. So here you can see actually the two robots are communicating with each other. What is really cool here is, I mean, it's not very fancy graphics or anything that I have to show you here, but what is really, really cool is that we can actually, this is their code running on the simulator. So the new gazebo set is ready to actually support such features. Next, we'll just let this go through and yes, as I said, it's recording because if I run gazebo together with Chrome, like I'm pretty sure my audio is going to drop and things are going to crash and burn. So this is running 100 times real time speed just for your information. Let's see. So, okay, if you've liked this talk, the code is available here at osrf-r-u-v. If you wanna get involved in maritime robotics as a new working group, I'll send you a link just now, later on. There are other cool things I haven't shown you and I was not sure if I'd have the time to do it. So we've recently added waves, wind. So waves is a very nice visual feature that can be seen. Ocean currents, depth elevation maps, there's a lot more that I have not covered in this talk because I've only got a limited time span to speak. But if you are interested in implementing in this field, few things to note, gazebo can be installed. The latest gazebo can be installed. We can join our communities. And there's also, as I said, a new maritime working group where the focus is really on underwater robotics and how we can use open source tools to follow the underwater robotics field. There's a QR code, you can scan that, you can join that. You can join our matrix chat. And finally, I just like to say thank you. I'll show you another shark video with cooler graphics. This was shown at Rosconn. This is using like our test data test. So it's not using actual code to run the stuff, but you can see an army of these robots. So I'll leave the floor open to questions now.


An AC motor is used in this electric razor. AC motors also rotate huge radar antennas. Electric clocks, drills, mixers, electric fans, the list of commercial appliances that use AC motors is almost endless, and it's getting longer every day. More important to you is the use of AC motors in electronic equipment, like this blower motor that is used to remove heat in some radio or radar sets. Without these motors, the build-up of heat would damage the delicate electronic components within the equipment. The point is, since AC motors are so commonly used in almost every kind of work, it makes good sense for you to learn as much about them as you possibly can. There are many different types of AC motors. There are synchronous motors, repulsion motors, universal motors, and induction motors. Of these, the induction motor is probably the one most commonly used because of several reasons. It's simplicity of construction, it's relative low cost, and it's ruggedness. For these reasons, you will see induction motors like this one that supply only a fraction of one horsepower. Others will vary in size according to the job they must do. So in this lesson on AC motors, we'll concentrate our attention on the induction motor. Once you understand its operation, it's a simple matter to understand the operation of the other types. Now to begin our examination of the induction motor, let's take a look at how it's put together. It's physical construction. Oh, don't worry about your TBI guide for a while. We'll fill it out during the review after we finish the discussion. Bob? Okay. This is a typical induction motor disassembled. Now as we've said, it's very, very simple. We have the two end bells, the stator field windings, and the rotor. Now let's take a look at these end bells. The end bells are used to house the bearings or the mounting devices that hold the rotor shaft in place. Now notice there are no brushes or complicated brush holding devices at all. Just simply hold the bearings. And also inside the housing or inside the end bells, we would find the housing that contains the stator field windings. Now notice the simplicity of construction. We have the stator field windings, the iron core. Very, very rugged and very simple. Inside the stator field windings, the rotor. Let's take a look at this rotor. All right, the rotor has no commutator, no slip rings, and no wire windings. It doesn't look at all like the rotor used in DC motors, does it? Not at all. Now this particular rotor design is called the squirrel cage rotor because it resembles the exercise cages used for pet squirrels. And like the squirrel cage, the rotor is very simple to construct. Simplicity of construction, which of course leads to lower cost of manufacture, and a very rugged design, makes the induction motor a very popular one. There are no wires on the rotor to burn out, no brushes to wear, no commutator to get scratched or pitted. All in all, a pretty good motor. Of course it's not perfect for every application. It does have certain limitations. But even so, it's used quite extensively. Now there are several types of induction motors, but they all operate on the same basic principle. The same basic principle which can be illustrated like this. Okay, what we have here is a cardboard disc, and on the disc we have, it's mounted on a pivot by the way so that we can spin it, and we have two permanent magnets glued to the disc. Thus if we spin the disc we have a rotating magnetic field. Now the principle we want to show you here is that if we take another magnet such as this compass needle and put it on the pivot, in other words so it's free to rotate, and we spin the cardboard disc we have a rotating magnetic field. Now you'll notice that the compass needle picks up the rotation of the rotating magnetic field, tries to align with it. Now this is an extremely important principle. Let me show you that again. We have a rotating magnetic field, we have a compass needle, look at it pick up the rotation of the rotating magnetic field, as it tries to align with the field it begins to rotate. Now this principle is the one that makes the AC motor operate. In the induction motor, the moving, or the rotating magnetic field is supplied by the stator field winding. And the rotor follows this field movement because it becomes an electromagnet. In other words, when current is applied properly to these windings, a magnetic field is generated that rotates about the housing. Now the field windings do not move themselves, and this rotor is not a permanent magnet. But watch what happens when the rotor is placed inside the field windings. And the power is applied. The rotor rotates. Now it's not physically connected to the field windings in any way, but it does rotate. Why? Simply because the field windings are providing a rotating magnetic field that induces a voltage into the rotor that causes current to flow, and the rotor becomes an electromagnet. And once it's magnetized, it's got to follow the rotating magnetic field, just like the compass needle did. All right. Now, Bob, we should point out that this rotor is not the correct size for this motor. No, it's a little smaller than the one that belongs in here. Well, we've used a smaller rotor to emphasize the fact that there is no physical connection between the rotor and the field windings. Actually, there are two major points to discuss in order to understand how the induction motor operates. First, we must have a rotating magnetic field produced by the stator windings. And second, we must cause the rotor to become an electromagnet. So let's first determine how we can produce a rotating magnetic field. Okay, coming up. Now, these four coils represent the stator windings of the induction motor. Actually, they're wound to act like solenoids for this demonstration. And we made them out of a deflection yoke from an old television set. Of course, the stator windings in the induction motor are not made exactly like this. But the magnetic field produced is essentially the same. Now, this switch on the bottom will allow us to apply certain voltages with certain polarities to these coils. And on this chart, we'll show these polarities during each increment of time. Now, in the center of the coils, we've placed a permanent magnet with an arrow on it to show the direction of the magnetic field at any one time. Now, this permanent magnet is simply glued to a ball bearing so that it can rotate freely. Now, the object of this demonstration is to cause this arrow, this magnet, to rotate 360 degrees by causing the magnetic field produced by these coils to rotate 360 degrees. So that you can understand exactly why this happens, let's take a look at the way these coils are wound and how the voltages will be applied. Now, actually, there are really only two coils. We'll call them L1 and L2. L1 was wound something like you see it. And then the core was cut in the middle and stretched apart. Now, still one coil, but now it's got a gap in the middle. L2, the other coil, was constructed in the same way. Now, L2 will supply a horizontal magnetic field and L1 will supply a vertical magnetic field. So if we supply voltage to just L1, we'll, of course, cause a vertical magnetic field. And the field lines up like this. Now, this arrow, like the arrow on our trainer, points to the north pole of this magnetic field. Right up here. And right here, Tom, we should point out that you can apply the left-hand rule and determine the magnetic polarity of these coils. We're not going to take the time to do it now, but it would be a good idea for the students to do that and they could actually prove that what we're saying is quite true. Right, that's a good point. Another good point is, if we reverse the polarity on L1... Make this a negative, in other words. Right. We'll, of course, reverse the direction of the magnetic field produced by L1. And the rotating magnet will, again, line up with this magnetic field. Now, the same thing, of course, applies to L2. With voltage applied only to L2, we'll produce a horizontal magnetic field. Like that. And if we reverse the polarity applied to L2... We'll go from positive to negative again. We'll, of course, reverse the direction of the magnetic field. Now, from this, you should see that we can already produce four magnetic field directions up, down, left, and right, simply by supplying the proper polarity of voltage to each coil. And we can also energize both coils at the same time and produce four more directions. Now, by supplying both L1 and L2 with this polarity, L1 produces an up direction, L2 produces a left direction, so the two equal fields combine and move up and left at this angle. And, of course, if we reverse the polarity on both coils, we would, of course, reverse the direction of the magnetic field. We're going from positive to negative again. Like this. Exactly opposite polarity, and we reverse the direction of the magnetic field, causing it to move down and to the right. Right. Well, that essentially is what we're going to do in this demonstration. Simply supply voltage with the proper polarity to cause a magnetic field to rotate 360 degrees in a clockwise direction. Right. Now, we could just as easily produce counterclockwise rotation by reversing the direction of the windings on L1 and L2, but we chose clockwise. All right, Bob, let's reset the demo to the time zero position. All set. Now, at this position, the pointer indicates zero degrees. It's pointing straight up. From this, we know that only L1 has voltage applied to it. The graph shows that the value of this voltage is a positive 10 volts. At this time, of course, L2 has no voltage applied. All right, switch it to time one. There we go. Now, at time one, the pointer is indicating 45 degrees. Now, this tells us that both coils must now have voltage applied to them. Now, the voltage on L1 has dropped to 7.07 volts, and the voltage on L2 now has risen to 7.07 volts. All right, switch it to time two. At time two, the pointer shows that only L2 now has voltage applied. It's at maximum positive 10 volts. L1 is now at zero volts. At time three, the pointer again indicates that both coils are energized. The graph shows L2 at positive 7.07 volts, and L1 now at negative 7.07 volts. Now, notice that the polarity on L1 has been reversed. This was done to reverse the direction of the magnetic field produced by L1. It's now down instead of up. Now, think time four will prove this, Bob. Sure will. Now, only L1 has voltage applied, and of course it's negative 10 volts. Now, see the difference between time four and time zero. At time zero, L1 was at max positive. The pointer showed that the magnetic field was moving up. However, at time four, L1 is at max negative. The polarity is reversed, and the pointer shows that the magnetic field is also reversed. Okay, Bob, switch it to time five. Now, once again, the pointer shows that both coils are energized. Now, notice that we also have reversed the polarity of voltage applied to L2. Now, both coils are at a negative 7.07 volts. At time six, and only L2 has max negative applied. Now, L2's field has reversed as indicated by the pointer. L1 at this time has zero volts applied. Now, at time seven, both coils energized. L2 at negative 7.07, L1 at positive 7.07. And at time eight, at time eight, we're back at zero degrees where we started. And our voltages and polarities are also at the same values we started with. L2 is at zero volts, L1 is at max positive. So we have rotated the magnetic field 360 degrees. But we used DC voltages to do it. And this is supposed to be an AC motor. Well, look at the graph of the DC voltages that we used to produce one revolution of the magnetic field. Here are the voltages applied to L1. And here the voltages applied to L2. Look familiar? Yeah, you sure do. If we connect all the voltages applied to L1 and all the voltages applied to L2, we find that we have two AC voltages that are 90 degrees out of phase. Well, that's why we use 10 volts and 7.07 volts. Now 10 volts is the peak voltage of these AC sine waves. When we divide the sine waves into 45-degree segments of time, we see that these points are exactly 7.07 volts. So using these values, we constructed a sine wave that moved through 360 degrees. And then by applying these values to the trainer, we move the indicating arrow through 360 degrees. The important point for you to remember is that two out of phase AC voltages will cause the magnetic field to rotate just like the DC voltages. Only with AC applied to the coils, the rotation will be a lot smoother and we won't need a mechanical switch. The voltage values and polarities will change automatically as the input AC changes. Now another point is one cycle of AC produces one revolution of the magnetic field in the example that we just used. Now the actual speed of the magnetic field of an actual induction motor would of course depend on the design of the field windings, the number of pole pieces, and of course the frequency of the applied AC. Now these field windings have AC applied to them. Not yet. Now they do. Oh, you turn the power on. Okay, I'll start over. These field windings have AC applied to them in the proper phase relationship. They are producing a rotating magnetic field, which is easily proved when this chunk of iron is dropped into the field. Proved, I'm not really easily because the magnetic field is attracting the rotor toward the standard. Now we've got it. Yeah, we've got it in there now and if I let go of it. It rotates. Right. And obviously something must be causing it to rotate. And that's something, the rotating magnetic field. Right. A rotating magnetic field. But how does this cause the rotor to become an electromagnet? Well, you remember the requirements for induction? I sure do, a magnetic field conductor and relative motion. All right, we've got a magnetic field here that's rotating about the field windings. I'm going to take the rotor out of there and prove that we have induction taking place. Why don't you explain what you're talking about? I'm going to do that. This is a coil of wire. The ends of the wire are connected to a resistor that is connected to the leads on our PSM-6. The object is, if we get current to flow in this loop, we'll have current flowing through this resistor. We'll get a voltage drop and we'll read the voltage on the PSM-6, okay? Okay. All right, now I'm going to take the loop of wire and place it in the field windings. Now I want you to watch the meter on the PSM-6 here. Let me apply the juice first. You may hear a little hum being picked up by the microphone because of this magnetic field. Now, as I place this loop of wire into the field windings like this, you see the PSM-6 indicating a voltage value. That's induced voltage, huh? That's right. That's the induced voltage from this loop. And you can see that I take the loop out, it goes away, put the loop back in. I've got to get the loop all the way down in there. There you go. Now we have the rotating magnetic field inducing a voltage into the loop, which we're reading on the PSM-6. Now the important thing to realize here is that once we get current flowing in this loop, once we get a current flow in this loop of wire, we have a magnetic field established about the loop. Now this means that we'll exhibit a north pole on one side and a south pole on the other. Or in other words, we have magnetized the loop. Made in an electromagnet. An electromagnet, right. Now actually, the rotor is the same thing or almost the same thing. And a rotor is made in a very, very similar way. Instead of using windings of wire, however, we use conducting ring on this end, conducting ring on this end, and they're joined together by conducting bars, these little white lines. And the reason I say conducting, sometimes they're made of copper, sometimes aluminum. This one happens to be aluminum. Now current, as the rotating field goes around this rotor, current is caused to flow in the rotor, which sets up a magnetic field and the rotor develops a north and a south pole. Now once we magnetize the rotor, it has got to follow the rotating magnetic field as you've already seen, just like that. Okay, that's it. The rotor follows the rotating magnetic field as soon as it becomes an electromagnet. Same thing that occurred with our little demo, the permanent magnets on the card with the compass needle. You should point out, Bob, that the rotor also has a core made of... Right. Now the rotor is a little different than the wire loop because it has an iron core or a material that has a low magnetic reluctance. Now this, of course, concentrates the magnetic field and makes the rotor a stronger magnet. So the rotor turns following the rotation of the magnetic field. But, Bob, how fast does the rotor turn? Well, to answer that one, we've got to reconsider the requirements for induction. You remember the requirements. I sure do. The magnetic field, a conductor and relative motion. Now this relative motion is between the magnetic field and the conductor. And, of course, if there's no relative motion, then there's no induction. That's right. So we know from that, then, that the rotor cannot turn as fast as the magnetic field because if they were both turning at the same speed, there would be no relative motion between them, no relative motion, no induction, no induction, no current flow in the rotor. And, of course, if we didn't have current flow in the rotor, there would be no magnetic field, no magnetism in the rotor. The rotor would just be another chunk of iron. And we also know that it can't turn faster than the magnetic field because the magnetic field is what causes the rotor to turn. That is, it's the driving force. So if the rotor can't turn faster than the magnetic field or even at the same speed, the obvious conclusion is that the rotor must turn slower than the magnetic field, right? Absolutely brilliant conclusion. Good. But tell me, Bob, how much slower? Ah, now, that depends on two things. The amount of internal loading and the amount of external loading. Now what do we mean to that? Internal loading refers to the drag or the load on the motor caused by weight and friction. You mean like it would be easier for a little guy like me to push a small light car than it would to push a big old heavy clunker like yours? It'd be easier for anybody, Tom. Especially me. Right. The same thing is true of this rotor. That is, it takes a certain amount of energy to overcome its weight to cause this hunk of iron to turn. And, of course, the friction of the rotor shaft on the bearings adds to the internal load. And there's a little cooling fan built into the rotor, and that increases the internal load. Now the external load refers to the job or the work that the rotor must do. That is, turn gears or operate pulleys or maybe turn a fan blade. That you just happen to have with you. Happen to have one in the pocket, right? Very good. Now when we put this fan blade on the rotor, we have increased the load or the drag on the motor. And therefore, it's going to turn a little slower. In fact, I've got to give her a little start there to get it going. Now it turns slower. Now before, the rotor was turning almost as fast as the magnetic field under a no load condition. Right. Now it slows down a little. Well, it slows down a lot because it's got work to do. There's more drag on it. Right. That's the way. So the rotor does then turn slower than the magnetic field. I think we've proved that point, Bob. Right. Now the difference between magnetic field rotation speed and rotor rotation speed is called slippage. And the greater the load on the motor, the greater the slippage. That's right. Now since we've put a load on the motor, this fan, in other words, we've caused the rotor to turn slower. Well, how do we generate enough energy to keep that rotor turning? That's a very good question, Bob. And I hope you've got a good answer. Ah, we do. The rotor becomes an electromagnet, right? Right. But how strong an electromagnet is the rotor? How strong should it be? It should be just strong enough to do the job, in this case, to keep the fan blade turning. The strength of the electromagnet is determined by the amount of current that flows through the conductors of the rotor. The more current, the stronger the magnet. And so therefore the current in the rotor is determined by induction. I've heard that somewhere before, induction. Well, we know that the magnetic field strength is at some fixed level, depending on the applied voltage. And we know the number of conductors in the rotor is also fixed. So the only variable factor that could affect the amount of induction is the relative motion between the magnetic field and the rotor. Is that right? Exactly. So if we increase the relative motion, we increase the rate or the frequency at which the conductors are cut by the flux lines of the rotating field. The greater the frequency of cutting, the more the current in the rotor, the more current in the rotor and the stronger the magnet. Now, that's why the rotor can continue to turn the fan. The load of the fan causes the rotor to slow down, just as I can do with my finger here. I can cause the rotor to turn slower. As it slows down, the slippage increases. And the frequency at which the conductors of the rotor are cut by the rotating flux lines increases. More current flows and the magnet becomes stronger and compensates for the increased load. Now, there's a limit to this. I thought there would be. For example, if I make the load on the motor too great, as I'm doing here with my fingers, it stops. But the magnetic field is still zipping around there, right? Right. Nothing slowed it down. No. So the frequency of cutting has gone way up. Now from this, you might think that the current in the rotor, when I've got it stopped like this, has also gone way up. But that's not so. Look at this. As the frequency of cutting, which is F in this formula, as the frequency of cutting goes up, X about the inductive reactance of the rotor also goes up or increases. Now we know if the reactance of the rotor increases, then of course the current in the rotor is going to have to decrease. Right. So at this high frequency of cutting, that is when I've got it stopped, I'm holding it stopped, the reactance of the rotor becomes large enough to limit the amount of current flowing in the rotor's conductors. So too great a load will stop the rotor by increasing its reactance to a point where the current decreases. And of course as the current decreases, the strength of the electromagnetic field decreases, the motor can no longer do its job and it stops. Now actually, trying to operate a motor with too great a load on it will result in damage to the motor. And of course that's why motors are rated for different loads. That's very logical. Okay. Now this curve, which is known as a torque curve, will give you some idea of the relationship between rotor rotation speed, magnetic field rotation speed, and the turning force or torque generated by the motor. Now with no load on the motor, the speed of the rotor is almost equal to the speed of the magnetic field is not all that much holding it back. But as the load is increased, as when Bob put the fan blade on, the rotor begins to slow down. The rate of cutting increases and torque increases, compensating for the added load. But at this point now, torque is maximum. Now if the load is increased any more as when Bob held it with his fingers, the rotor of course must slow down. The frequency of cutting goes way up to the point where the inductive reactance becomes large enough now to start limiting the current flow in the rotor. The strength of the electromagnet decreases, torque decreases. The motor stops and begins to overheat. Now if left in this condition, of course, the motor will be damaged. Now the point on this curve where the motor is designed to operate is just about here. Now this allows the load to change slightly without upsetting the stability of the motor. Okay, so the rotating magnetic field then induces a voltage into the conductors of the rotor, causing it to become an electromagnet. It exhibits a north and a south pole. The rotor turns at some speed determined by the load, both internal and external load. Now the difference in speed between the rotor and the magnetic field is called slippage. All right, that is the AC induction motor. Very good Bob. Now to summarize, let's complete the TVI guide. Okay, I'll take item one, which asks you to identify the major parts of the induction motor. A, the end bells. Remember they just hold the bearings for the motor. B is the housing and the stator windings. Very simple and very rugged. And C, of course, is the rotor. There are no slip rings or wire windings. And of course overall construction is very simple, very rugged. Okay, item two. Very good, I'll take this one. The basic principle of operation of the AC induction motor is conductors placed in a rotating magnetic field will become magnetized and if allowed to rotate will follow the moving magnetic field as the rotor is doing in this case. All right, take number three, Bob. Okay, a rotating magnetic field is achieved by applying out-of-phase voltages to the stator or the field windings, which we represented on this demonstrator. Now you should point out, Bob, that the most effective phase difference to use is 90 degrees as we did. It'll work at other phase differences, in fact any phase difference other than 0 or 180 will give you a rotating magnetic field. But as you said, the most effective, the most efficient one is 90 degrees phase difference and that's the one that's probably most commonly used. Right, now I'll take item four. All right, help yourself. All right, item four, the rotor acts like a magnet. Well, it actually becomes an electromagnet and follows a rotating magnetic field because of induction. Okay, and we proved that with this little loop of wire, the resistor and the PSM-6, we put the loop in the field windings and the PSM-6 showed us that we did have a voltage induced into the loop, causing current to flow. Once we had current to flow, we know that the loop had to become magnetized and exhibited north and the south pole. And once we get it magnetized, it has got to follow the rotating magnetic field. Which brings us to item five, which I believe you can have. Exactly. All right, the rotor of the induction motor does not rotate as fast as the magnetic field because of several forces that act on the rotor. One, the internal load, that is, rotor weight, the little fan, the bearing friction, and so on. And the external load on the motor, such as the gears, pulleys, or the fan blade, or in this case my finger. As I squeeze it a little bit, you can see that it turns slow. Whatever work the motor does. So the rotor has got to go slower than the rotating magnetic field in order to have relative motion so that it can become an electromagnet. Which brings us to item number six in the TVI guide and my turn. Slippage is defined as the difference between the speed of rotation of the magnetic field and rotor rotation speed. Right. Okay. And remember this slippage is an extremely important one, Tommy, because without a difference in speed between the rotor and the rotating magnetic field. Well, we won't have an electrical magnet. Right. We wouldn't have relative motion. We wouldn't have induction and the motor wouldn't work. So slippage is an extremely important aspect of the induction motor. Now, can I get item seven? I'll get it. All right. Item seven shows you how one complete revolution of the magnetic field is accomplished by applying these out-of-phase voltages to the stator windings. Now, you can study this very, very carefully so as to fix the principle in your mind. Which was? By the way, we might point out, Tom, and once again, that you can apply the left-hand rule of all these coils and prove precisely what we've said, right? We can develop a rotating magnetic field. I'm certainly glad you said that. A rotating magnetic field? A rotating magnetic field? That induces a voltage in the rotor causing it to become an electromagnet. Right. Which will follow the rotating magnetic field. Simple. And rugged. And economical. Right. The AC induction motor, because of all these facts, will be found very, very widely in your career as a technician. So study that TBI guide and learn all you can about it. I sure will. You too.


When you pray there needs to be an earnest expectation of God moving There also needs to be a willingness for you to accept how God moves in you. That means you're not telling God how to move You're just accepting how he does move. I pray for God to remove a destructive pattern in my life And his response was to expose everything sinful followed by prison It was the absolute best thing for me. Although at the time I hated it But no discipline seems right or seems good at the time that it's happening But that's what God does to a child of his whom he is disciplining But now I thank God for faith is trusting God trusting where he's leading why he's leading But more importantly that he's leading and that you are letting him lead Faith is not asking for your outcome. Faith is trusting that he will get his outcome Faith is not asking for your will be done But faith is asking that his will be done and you're okay with that


Hello everybody! Hi! Welcome to the Children's Museum and Theatre of Maine and our Fall 2018 production of Charlotte's Web. This is based on the book by E.B. White and adapted by Joseph Robinette. We're so excited that you're watching us today. Thank you very much and enjoy the show. Listen to the sounds of the morning. Very, very early morning. So early, in fact, the sun isn't even up yet. Listen to the crickets, the good owls, a frog down by the pond, a dog up at the next farm. And today's is another song. It tells us something exciting happened during the night. Some brand new kids came. Here's one of them right now exploring his new home. His name is, well actually, he doesn't have it in yet.  But as you'll see, he's not just any ordinary pig. Who am I? Where am I? Never been here before. Never been anywhere before. Everything's so, so strange. But I like it. I think. This new pig has been born here at the Aribals Farm. Before long, we meet the Aribals. We also meet the others, the people and the animals, who play an important part in his little pig's life. Now where should we start? Wait a minute. We've already started. It's early morning. We're at the Aribals Farm. It's a big and some warm. For now, that's all you need to know. Some pigs were born last night. Well, I don't think mine even acts. Well, one of the pigs is a wretch. It's very small and weak, so your father's decided to do away with it. Oh, gosh. Stop him. Yeah, there's... Stop, Fern. Don't yell. Your father's right. It would probably die anyway. Fern, I know more about raising a litter of pigs than you do. A weakling makes trouble. Now run along. I'm born small. Could it? This is the most terrible case of injustice I've ever heard of. I'll let you take care of it for a little while. For doing over there. Your sister has a guest for breakfast, Avery.   It's nothing but a runt.  The school bus will be along in half an hour.  Can I have a pig too, Bob? No. I only give pigs or early risers who want to rid the world of injustice. Let's eat. Pissing bottle.  Hey, what's his name anyway? You're along now. I have to name you. It's a perfect name for a perfect pig. Not for you. Clarence.  Now to have something besides just milk. Try this bowl of cornmeal mush. And honey. Chock it up to good clean living. And to good fattening food. Okay, pig. It's time you graduate the slops. Skim milk. Potato skins. Potato skins. Leftover sandwiches. Leftover sandwiches. And marmalade drippings. Marmalade drippings. I'd say it's about time for a birthday party. He was big. Now let them call me a runt. Check out the pink in the cheeks. Eating too much. I can't provide for him any longer. I've already sold Wilbur's to his brothers and sisters. Wilbur sometimes keeps a pig. And if Wilbur goes to live there, you can go down and visit him any time you'd like. Oh yes, please. That's not a bad idea, Martha. Come along. We'll call on Wilbur. Can Wilbur come too? Why not? Maybe we'll let him make the call himself.  She goes back doors back so they couldn't give her the pink sauce. As it's worse. I couldn't let down Fern, could I? I mean, she seems so desperate. And besides, she only asks six dollars for it. And when it gets big enough to slaughter, it'll be worth a lot more than six dollars. What? Quick for a pig. Oh, here's the name, does he? I just made a big can of peaches.  The horse is in the house. It has a peaceful smell. I saw nothing bad could ever happen again in the world. Fern was right. It is very nice here. It's nice to have a pig around the place again. I'm gonna have delicious leftover slobs in an age. Oh, but the slobs will be for me. I'm sure you'll find it in your charitable little heart to share your food with dear old Templeton, especially if I make my nest right here beside your truck. What is all the commotion in here? It's the oval jeep. We overheard the supplements discussing you. They plan to keep you nice and comfortable.  Oh, I am going to love it here. Just the same. We don't envy you. You know why they want to make you fat? They say nothing at all. Nice to meet you, Wilbur. Lamp, mind your manners. Nice to. My pleasure. I'm sure. Well, I have a trash pile. I'm sure about Templeton. And I'm a trifle concerned about the old chief's remark.  Well, I don't know. And the old chief didn't tell me. Well, I'm much too tired to worry about it now. I'm going to sleep. Go to sleep, Wilbur.  Horse, take a walk. The map out. Horse, take a walk. Take a hole. Ten o'clock. Fill in the hole. Eleven o'clock. Just stand still and watch the flies. The bees in the swallows. Twelve noon. Who lunch? It's the fence post. Four o'clock and four thirty on. I've watched you all night.  Who are you? And this will do the trick, Wilbur. Now, he won't like this medicine, so you have to hold him down and I'll feed it to him.  It's sulfur and molasses. It'll cure what ails you. I'll give him a second dose. Just a good measure. I think he'll be well in no time. Marty just spoke to me. Make himself or herself known. The fancy way of saying hello. Well, salutations to you too. May I have your name, please? My name is Charlotte. Charlotte what? Charlotte? I'm a spider. I think you're beautiful. Thank you. And your web is beautiful too. It's my home. I know it looks fragile, but it's really very sturdy. Protects me. And I trap my food in it. Oh, I'm so happy you'll be my friend. In fact, it restores my appetite. Will you join me? No, thank you. My breakfast is waiting for me on the other side of my web. Oh, what do you happen? A fly. I caught it this morning. You eat flies? In bugs. Actually, I drink their blood. It's the way I'm made. I can't help it. Anyway, if I didn't drink the blood of flies and bees, there'd soon be so many of them that they'd take over the world, wipe out everything. Well, I wouldn't want that to happen. Now, if you'll excuse me, I wouldn't have my breakfast. I've got a new friend, all right. But Charlotte is brutal, I think, and bloodthirsty. How can I learn to like her, even though she is very pretty and clever, it seems? Wilbur was suffering the doubts and fears that often go with finding a new friend. But, as the days passed by, he slowly discovered that Charlotte had a kind heart and that she was loyal and true. Spring would soon become summer. The early summer days are a jibbly for birds. From the once, the white thro- For the happiest and fairest of the year, lilacs and apple blossoms bloomed, the days were warm and soft, and now the school's over, I can come visit the barn almost every day. Four weeks of unremitting effort on the part of our friend, the goose. The gosslings have arrived, and here comes our proud mother right now. The father is also to be congratulated. What happened to the other egg? In collection. Imagine wanting a junky old rotten egg. Let's hope this egg never breaks.  Don't worry, I won't break it. I handle stuff like this all the time. Let's put it right here in the trough of my other things. Here's some good news. Uncle Homer and Aunt Edith seem to be glad that you're putting on weight. Sure they are. And you know why, don't you? You asked me that once before, but you didn't tell me why.  He has to learn sometimes. Learn what? At that news.  So they can what?  Turn you into smoked bacon and ham. It'll happen when the weather turns cold. It's a regular conspiracy. Stop! I don't want to die. I want to stay here, read the beautiful air. Certainly making a beautiful noise. But I don't want to die. You were quite down. I am. How? I'm afraid that remains to be seen. Burned. Pray it free. How does that mean to you? You're gone. Charlotte Fordevers. And you're going to do to save Wilbur. Who's Charlotte? I'm straight over there. It's Drametjus. Leave him alone, Amberie. That said, you were going to keep them from killing me. I've never been more serious in my life. How are you going to do it? I'm not sure, but I want you to get plenty of rest and stop worrying. Good night, Charlotte. Good night. Thank you, Charlotte. Good night. What to do? Save Wilbur's life and I am determined to do that promise. Wait a minute. The way to save Wilbur's life is to play a trick on the supplement. If I can fool a bug, I can surely fool a man. People aren't as smart as bugs. Of course. Let's odd be easy, but it must be done. First, I tear out a section of my web, leaving an open space in the middle. Next, I leave new threads to occupy the space. Swing the spinnerets, let out the thread. The longer it gets, the better it's run. Attach, ascend, repeat, descend, pay outline, messages spun, friend. Some pain, girl, for the first time around, but it was quite exhausting. Then I catch a little nap before deepening. I have the most terrible dream. I dreamt there were men with guns and knives coming out here to take me away. Thing here but me. He saw me. He saw that I'm big and healthy and ready to be made into guns and knives. Right now, I just know it. What can I do? Let's be something literally patched up. Maybe it's loose again. I have to try. See them freedom for the frying pan. The first, a little sustenance breaking out of this prison. Well, we have no ordinary. No, it's the pink. It's unusual. Mistress, how about the miracle? Then call the aerobels. Hurry. You know, I always knew this piggy bar was just quite a good one. I'd say it's some pig. Come on now, Larry, work to do. I'm sure there'll be lots of visitors from one of these things out. Things to have worked, at least for the time being, but if we are to save Weber's life, I'm going to have to write more words, which means new ideas. Any suggestions? How about big supreme? No good. Zuckerman, does anyone here know how to spell their project? Hamilton only helped himself. And what's up? Did you see the message in the web? It was there when I went out this morning. So we could deal. It was a big deal to Zuckerman. And now, Charlotte needs new ideas. When you go to the dump, bring back a magazine clipping, and Charlotte can copy the words. It'll help save Weber's life.  I should worry. You should worry next winter when Weber is dead, and nobody comes around here with a nice pile of socks. I'll cook in a magazine clipping. And the sun, Weber. I need a little rest. Thank you, Charlotte.  News about the word in Charlotte's blood began to spread throughout the county. People came from miles around. Here's the wonderful pigs, where I clear up into the hills when farms talked about the miraculous animals after this time. Charlotte knew there'd be even more visitors the next day. So, that night, were the other creatures that she began to work on her web? Weber gets the letters read. Spinning and weaving, she began to form the new letters. Attach, ascend, repeat. Weber, steady, now for the R. On through the night, the spider worked at her difficult task, which was nearly morning when she fell asleep. The message was spun up to the end. He ate the small bug she was saving. After that, she fell asleep. I think I spent the entire day and night outside sleeping. Oh well. It's very refreshing, especially in the summertime. I'm afraid. No one can happen again. Well, then tell them what's happened. You may want to bring a photographer. Plainest day. Terrific. I can't believe it.  I don't know where to put them all. We can park the vehicles in the open field. Every now and then, I'll do our traffic. Funny work to do. We have to get ready for the visitors. We do. I think I'll help you.  Of course not. They will never spoil me. Anyway, you still have to worry about this future. His life is not here yet. I know. I can face anything with friends like you. Church is one of the most satisfying things in the world. You better believe it, Buster. And you better not forget the friendship of old Templeton. It just happens to be at the dump all night looking for words to say you. From an empty package of soap flakes. I have to see you in action this year for if you are... First piece of apple strudel she's making for the visitors. Mr. Zuckerman's even talking about bringing you to the county fair. Follow this excitement. Continue. For at least another month. When I'll be making my egg sac and filling it with eggs. You could lay your eggs at the fair. Lover said they were just thinking about taking you to the fair. If the excitement continues. New words. So I better start writing one right away.  I'm writing if they come by. Get out of the way. I have to come to the fair too. Somebody, somebody, somebody has to run errands to do Java work. I'm staying right here. I have no interest in fairs. That's because you've never been to one. A fair is a rat's paradise. Everybody spills food at a fair. Popcorn, frozen custard, candy apples. Stop it. That's enough. You've twisted my whiskers. I'll go. Attach, ascend, repeat. Cheryl, it's working fast so fast. I hope you all got in the hang of it right now. Look. Here comes the visitors. It looks like a photographer and a reporter. Hurry, hurry. One, two, three. They're almost. Spitting webs, but I can try. Oh, that's okay. I'm done. And the photographer. Let me get my wife and my heir to end in there too. Loverby, Edith.  That's it. I've got something for you to write in your newspaper. I'm bringing this pig to the county fair. And if he can win a blue ribbon, I guarantee we'll never make him to hammer bacon. Oh, what happens? They harvest thoughts of school and the county fair. Come one, come all. Foot long hot dogs, giant hamburgers, french fried potatoes, all this and more at the Lions Club barbecue pavilion at the fair. We can go with you. Let's let the children go off by themselves. The fair only comes once a year. Thank you, Papa. He's got to win that blue ribbon tomorrow. Tomorrow's the big day.   You hear me? Oh, Ed. Is it coming? Oh, do you think they'll be all right, John? Well, they've got to grow up sometime. And a fair is a good place to start, I guess. Here's the sign for water. Good, Loverby. Well, put it right here so everyone knows.  Zuckerman's famous pig. That's fine by me, Loverby. Maybe all of it even wouldn't one of those Napao blankets I've been hearing about. Isn't it nice to be at the fair? I'm just as excited as the kids. Ed, Ed, can we go see the new tractors? Let's you and me wander down to the cattle barn and check out the hostines and the gurlies. Okay, but let's keep an occasional eye out for friend and Avery. All finished. We'll meet you back there in a little while. I thought they'd never leave. It's much easier for a rat to hide out in a barn in the open like this. Well, I think I'll do a little exploring. Please bring back a word, Templeton. I'll do what I can. I'm sure there'll be bigger pigs here and even better-looking ones. No, I'm just calling my uncle. You're rather large. Are you a spring pig? Sure I'm a spring pig. What do you think, a little spring chicken? Fun or the next step? Mildly funny. I've heard funnier ones, though. What are you doing over here? They're still working on them. I just wandered off. Look at my new mini when they say I'm gone. When I've seen it so far, I've got that blue all soda. But I won't need a new bell. Better be skinned back. Got 50 up for the crowd. I'm ready for a much bigger.  And if I'm not too tired, just spinning this new web earlier today to go on with my spring-looking fellow. I think I've heard it. Aren't you supposed to be that creative terrific? Over here. He's tricky. Well, here's your order. Going. I'm having trouble reading that. What's the word? Humble. H-U-M-B-L-E. Humble has two meanings. It means not proud and close to the ground. That's what we're all over. Well, I hope you're satisfied.  I came to this fair to enjoy myself. You've been very helpful, Templeton. You may run along now. Oh, I'm gonna make a night of it. The old sheep was right. This fair is a rat's paradise. What eating? What drinking? Bye-bye, my humble Wilbur. Fairly well, Charlotte, you old schemer. This will be a night to remember in a rat's life. Charlotte, what did you mean when you said this was going to be your last word? But Charlotte? That's wonderful, Lervie. Just lucky that's all. Come on, everybody. Come see what Lervie won. What is it, Irving? Congratulations. I do wonder where Fern is. She'll be along.  Will the pig be all right? Of course, Lervie. They have night watch for the look after the pigs and the people that left. Yeah, it'll be fine. Lucky day today. Let's just hope it's as lucky for Wilbur tomorrow. Oh, Fern, where were you? I've been worried about you. Oh, I met Henry Fussy. He invited me to ride with him on the Ferris wheel. Henry Fussy? He even bought a ticket for me. My, my. Let's load up, everybody. I hope you weren't too worried about me. Not really. Now that I know where you were. Thinking about you tonight, Wilbur? Sleep well. On Ferris, we'll ride with Henry. One time we stopped at the very top. You could really see the whole county. Or, at least I think it was the whole county. This is really going to be your last word. I don't know. I don't have much strength left. And tonight I have another job to do. Is it something for me? No. It's something for me for a change. Please tell me what it is. I'll show you in the morning. You're with me, Charlotte. I never feel lonely when you're near. Even if I don't win the Blue Ribbon. And the worst happens. You to say now, go to sleep. Good night. Long, Wilbur was asleep. Charlotte could tell by the sound of this breathing that he was sleeping peacefully in the strong. By now the fair was quiet and the people were gone. It was a good time for Charlotte to work. Though she was very tired, she worked quickly before she had another job to do. Before long, she finished writing in the web. To the end, the job finished. After she finished writing the new word in the web, she moved on to another project. It carried her far into the night. When she was finally finished, she was exhausted and she fell into a deep, deep sleep. Determine the winners of the Blue Ribbons. Judge Day of Wilbur's life. The winners of this and Charlotte's web. Humble. My goodness. Give that piggyback about a book back. It's okay. People are still going to come see them and what's written in the web. That's the spirit, Homer. I say we get to work. I'll give him his breakfast. I get the area. Homer, I think our sign needs to be a little more prominent. Prominently. It means more noticeable. It's probably for the voices of the cow. It sounds like somebody around here is going to get another award. Yeah. Mr. Homer's suffering. It says in the spider web. Yes, there are folks who might be trying to pay for that. Thank you. Appeared mysteriously on the spider web in Mr. Zuckerman's barn, calling the attention of all to the fact that this was some pig. Then came the word terrific and he is. Look at him. I eat today. The word humble. Once came this mysterious rating. This miracle has never been fully explained. We simply know that we are dealing with supernatural forces here. We should all feel pride and grateful. Now, ladies and gentlemen, most not take any more of your valuable time. On behalf of the governors of the fair, I take the honor of awarding the special prize of $25 to Mr. Zuckerman, Pansom bronze medal, which far outshines any blue ribbon to this radio. He gets these spells. He's modest and he can't stand praise. Well, I can't give a... I'll be running water. I'll celebrate the occasion by taking one last look around the midway. Sounds fine by me. Talking about, I'm done for. In a few days, I'll be dead. Charlotte, I'm so tired. I can't even climb up to my egg sack. Charlotte, my true friend. Come now, Wilbur. You alone to die. I shall stay too. Let you. Besides, even if you did stay, there would be no one to feed you. The fair runs would soon be empty and deserted. Wait. I have an idea. Listen to me. Charlotte is very ill. She will not be coming home with us. I must take her egg sack with me. I can't reach it and I cannot climb. Please, please, Templeton, get Charlotte's egg sack for me. What do you think I have, anyway? They'll be coming back soon. I will make you a promise.  First choice of everything in the trough. You mean that? I promise. I crossed my heart. All right. It's a deal. Use extreme caution. I don't want the same straw if you want to ride back home.  We'll take care of Wilbur, Edith. You just put up the tailgate of the pickup. Oh, Charlotte. Martha, you and her neighbor get in the trough. We'll be along with them. I don't want those governors of the fair to think surprised when he picked left the mess board. The fair dodged to be a mighty fine fair. Mighty fine. The mess board I've ever run through, the very best one. Well, come on, Wilbur. Put some in the rest of her strength and wave goodbye to Wilbur. You are well. You're never moving again. As the ferris wheel was being taken apart and the race horses were being loaded into their vans and the entertainers were packing up their belongings and driving away in their trailers. Charlotte dodged. We're soon deserted. The fields, empty for Lorne, a spider, played the most important part of all. Not one of them was there with her when she died. Wilbur returned to his beloved barn. The animals were delighted with him. All through the fall and winter, Wilbur watched over Charlotte's egg sack as though he were guarding his own children. Patiently, he awaited the end of the winter and the coming of little spiders. He's been out there in the dark for those eggs to hatch. Sampleton, you would live longer if you ate less. Flows will live forever. You do the honors. Sprouting. Including yourself. Sleep over. It happens every... But I wish they would stay. Some of them anyway. I'm being deserted by Charlotte's children. There, there, there, Wilbur.  Yes, I know. But I was just hoping that... Oh, never mind. Yeah. Salutations. Who said that? Me. See you too. Initial. A. Then my name is Arania. Pick a name out for me. Not too fancy. How about... Nelly? Welcome to your new home. It's a long story. And I'll tell you all about it.  Celebration of this very special day. I'm putting the medal where it rightfully belongs. Templeton, please put my medal on the hook where Charlotte's web is. Another favor. This is the last one. I promise. I know. Stop her children and her grandchildren dearly. None of them will ever take her place in my heart. She was in a class by herself. It's not very often someone comes along who's both a true friend and a good writer. Charlotte was both.


G'day mate 40 here So Notice a lot of people want to Pray their way out of a problem that they behave their way into all right, so I Don't think you can just pray the gay away for example without doing anything else Like if you behave your way into an addiction to gay sex I don't think you're just going to be able to pray your way out and I notice with a subset of Christians that the first response to a Problem they don't know how to deal with is well, I just ask people to pray for me And that's great, but I don't think you're going to pray your way out of a problem that you behaved your way into so let's say you have a problem with eating too much food or drinking too much alcohol or Looking at pornography or deading or under owning or Co-dependent relationships or An addiction to say an extreme amount of exercise or extreme devotion to sports All right, you behaved your way into a problem And I think you're going to pray your way out So I developed early on in my life a habit of maladaptive daydreaming. Well, I started out as adaptive. I would just Start daydreaming and my problems would disappear. So I just kind of bliss out when I was daydreaming But it's tendency for me to daydream and to Think of myself doing grand and fantastic and important things That that reflex of mine to just kind of bliss bliss out on fantasies of grandiosity I'm going to pray my way out of that like prayer can help. That's only one component So also, I noticed a lot of people think they can use religion to Get out of whatever problem that they're in.  You behaved your way into that Then I don't think You're going to be able to simply use religion to get out of a problem that you behaved your way into when we do something we fire neural pathways in our brain and then Neurons that fire together wire together and so we develop Maladaptive reactions to stimuli and or recovery means that our reactions to stimuli service rather than hurt us and it's so easy with a lot of the say the the process addictions to fool yourself to think that you're Making progress when you're not making progress or to think That you're not making progress when you are making progress So I was just listening to somebody talk today About how his sponsor gave him a list of about 10 things to do every day And if he does like at least six of them, he's making progress So that might mean one might mean make outreach calls to people in your program Another assignment might be to read 12-step literature another Some it might be to get on a meeting and other assignment to pray. That's one component other assignments to meditate Another assignment may be to track your spending Another assignment may be to track your time So I notice a lot of people I know they haven't ever 40 hour work week, but they're only actually working Maybe 15 hours of that and they're just goofing off the rest of the time And then they're wondering why they're always getting fired or they're stuck in a cycle where they just They just can't bear to work. So they just play spider solitaire. Is that a game or Some other some of the distraction instead of doing their job and they know it's not good They know it's not gonna work out and they know they're gonna earn a path of getting fired And it's an awful feeling to go around Knowing that if your boss knew how you were really spending your time at work He would fire you if your co-workers knew how you're really spending your time at work They would see to it that you were fired.  You've got an eight-hour work day. How much of the time are you actually working and Are you making priorities if you got too much work to get done in eight hours? You're making appropriate priorities and if you've got a Underrunning problem then then track your time not just at work But elsewhere are you watching three hours of Netflix a day? Is that serving you and then how are you spending your money? that you should be able to track how you spend your money so you know where everything's going and Make sure that you are using it to further what's most important to you and not get distracted So we behave our way into all sorts of problems with sex drugs food alcohol Relationships money and then it's so tempting to think there's like an easy way out Like I'm just gonna pray about this. It's gonna ask people to pray for me.  That means prayer and And Remember I'd often say to my therapist. I just wish there was like one small change that I could make so that then my life just You know completely transforms. Okay, I just want to Just want to make you know one improvement here that just has you know multiple repercussions positive repercussions all through my life And my therapist would would push me to make you know Big change large change dramatic change painful change And I just wanted to do the minimum. I just wanted to just Let me just make one little improvement here and then everything's going to be okay right, that's what I thought for decades if I just like Just change this one variable that everything's going to be fine or If I just embrace religion then that's gonna get a handle on my out-of-control sex life. I Just embrace religion. That's gonna get it get control of my out-of-control love life You know my need for constant, you know excitement and infatuation. I just get religion. That's gonna how we get control of my spending and my earning and my work life and my housing situation and my health and You can get control save your porn addiction But then you're I found that my addiction to acting out on social media Just like skyrocketed like when I stopped using porn that I started like posting like crazy on Facebook Not things that were necessarily my best interests You get I find I get control of like porn addiction the sex addiction the love addiction then the you know the acting out for attention or Food or watching too much sports starts rearing its ugly head and I've always wanted to take the easy way out Let me just finesse this and Taking the easy way out has been really really hard path for me. It has not been been pleasant Like I developed habits in school or cheating and I've managed to break that habit by the time I got to community college I only cheated one time in community college and never did it again. So I managed to break that habit but still that Instinct of trying to take the easy way out It's just it's just there under the surface because I fed it for so many decades of my life Like let's look for the easy way out here and sometimes for me seeking the easy way out is seeking repair of my life through religion when Religion is not going to be the primary component to repair that aspect of my life. I can make this radical transformation From atheists to converting to orthodox Judaism But that's not going to change any of my addictions because I behaved my way into these addictions and I'm pleased with my religious conversion, but it didn't shift any of my addictions. It didn't shift any of my habitual Expressions of bad character such as being inconsiderate. That's something I really struggle with being sloppy careless and inconsiderate of other people and considerate of how my behavior and my words and my choices and my effort or the lack thereof Impacts on them. So lack of consideration for others major a Character defect of mine that I just can't pray my way out of prayers being a component But I behave my way into these character defects I Can't just use religion and doesn't just like wipe out my tendency to lack of consideration I just take my tendency towards lack of consideration for other people and for myself Into my new religion. So I've not tended to behave with much consideration towards myself or with others So I find that people treat themselves considerably tend to treat other people with consideration And people who don't treat people with consideration tend not to treat themselves with consideration Then dishonesty I developed a habit early in life to avoid getting hit I would tell lies and so I developed that habit of dishonesty when under pressure to try to avoid punishment and Prayer and religion are just a small component of dealing with that character issue that that bad character addiction of dishonesty Self-seeking selfishness. All right, another The two major characteristics of my behavior over the course of my life, and I just can't pray those away And it's not that on the other hand from a toss but perspective. I don't I Don't work on my character, but there are all these things that I do to bring God in So God's there in the small still voice I believe or if you don't believe in God then embrace reality like reality is there and You can listen to reality or you can ignore reality and I want to have a positive relationship with reality so if I'm able to turn down the unnecessary noise in my life and Reduce the clutter in my life and the small still voice of God or the small still voice of reality however you Frame it then I can start to hear it So when I'm overwhelmed, I find it really helpful to clean and to organize.  I'm so tired from that. I don't know what what muscles I don't know why my hamstrings are so tight from Carpet cleaning and and moving and shifting things around So, you know 36 hours later my hamstrings are tight Still a little tired from that exertion, but cleaning things organizing things possession consciousness Really helps reduce my overwhelm Also, when I'm frustrated with people I find writing a long email to them and not sending it So do not put their their email address on the the Gmail draft Just just write it all out So I've been like waking up at 4 a.m. Sometimes like last Sunday and just like writing a long email to Person who was frustrating me and didn't send it. I just wrote it made it shine. It's a fine piece of writing talked about it with a with a friend and Then my inner drama queen kind of started to quiet down So, yeah writing everything out. I find Incredibly helpful because I tend to be overly dramatic overly excitable like respond in an excess way to a stimulus, you know jumpy and Yeah, the natural tendency to to seek out drama To feel dramatic when there's no inherent need for drama Be just excitable overly sensitive And so if I just write out everything that I'm frustrated about or feeling or perceiving I find it incredibly calming it never ceases to calm me and Never ceases to give me a feeling of satisfaction. It's like wow, that's a that's a great piece of writing Even though it's just a rant about my emotions. It's Fine stuff. Good job 40 Yeah, so writing things out talking them over with with other people who I respect and then prayer and meditations a component I find spending time around people I respect is a component making outreach cause is a component of a successful life getting on a 12-step meeting sponsoring and being sponsored reading 12-step literature Listening to inspiring talks or watching inspiring videos or reading inspiring books. So I'm reading a book right now by a guy I interviewed about two years ago Herb Lobdell So he's a judge and you wrote about Navigating the legal system and finding a spiritual path It's like, whoa, you know finding a spiritual path while navigating the legal system It's a pretty good book on Kindle That's it. Bye. Bye