Hello! Myself Sunil Kalshatti, Asset Professor, Department of Electronics Engineering, Valchand Institute of Technology, Solapur. Today, I am going to explain the three-phase semiconductor learning outcome. At the end of this session, students can analyze three-phase semiconductor. It is also called as a three-phase half-controlled bridge converter. Three-phase semiconductors are used in industrial DC drive applications up to 120 kW power output. Single coordinate operation is possible. Power factor decreases as the delay angle increases. Power factor is better than that of three-phase half-view converter. This is the circuit diagram of three-phase semiconductor. Load is highly inductive load and DM is the freewheeling diode. It is connected across the load. It consists of three SCRs and three diodes. The load is connected in between the cathode of SCR and anode of diode. Only one SCR from upper group and one diode from lower group conduct at a time, providing line voltage across load. The SCR, which is connected to phase, having higher phase voltage than any other phase is fired. The phase voltage Va becomes higher than Vb and Vc after omega t is equal to pi by 6. T1 is connected to phase A, so T1 is fired at omega t is equal to pi by 6 plus alpha. At omega t is equal to pi pi by 6, Vb becomes equal to Va and after Vb becomes higher than Va. So, T2 is forward bias and T2 can be fired at omega t is equal to pi pi by 6 plus alpha. The phase voltage Vc becomes higher than Va and Vb. After omega t is equal to 9 pi by 6, T3 is connected to phase C, so T3 is fired at omega t is equal to 9 pi by 6 plus alpha. The conduction period of D1 is from pi by 2 to 7 pi by 6. Conduction period of D2 is from 7 pi by 6 to ln pi by 6. The conduction period of D3 is from ln pi by 6 to 15 pi by 6. The conduction period of each diode is 120 degree. We define 3 line neutral voltages. As follows, Vrn is equal to Vn is equal to Vm sin omega t, Vyn is equal to Vbn is equal to Vm sin omega t minus 2 pi by 3 and Vbn is equal to Vm sin omega t plus 2 pi by 3. Here the phase difference is 120 degree. Vm is peak phase voltage of y connected source. Vrb is equal to Vac is equal to Van minus Vcn root 3 Vm sin omega t minus pi by 6. Vyr is equal to Vba is equal to Vbn minus Van is equal to root 3 Vm sin omega t minus pi by 6 and Vvy is equal to Vcb is equal to Vcn minus Vbn is equal to root 3 Vm sin omega t plus pi by 2 and Vry is equal to Vab is equal to Van minus Vbn is equal to root 3 Vm sin omega t plus pi by 6. These are the waveforms for alpha is equal to 30 degree. That omega t is equal to pi by 6 plus alpha t1 d3 forward bias. So, pulse is applied to the t1 and the current flows through the source t1 load d3. So, if you have to have this Vab appears across the load and the t1 d3 continuously conduct up to pi by 2. After pi by 2 the phase c becomes more negative. So d3 becomes reverse bias and d1 becomes forward bias and the current flows through the t1 d1 and when the t1 d1 conducts Vac appears across the load and the t1 d1 are continuously conduct up to the end of the half cycle. At omega t is equal to pi by 6 plus alpha t2 d1 becomes forward bias and the phase Vbc appears across the load. In this way the operation repeats. These are the current waveforms for I t1, Ia, I t3 and phase A. Average or DC output voltage of 3 phase semi-converter for alpha is less than or equal to pi by 3 or 6 degree and this mode is the continuous conduction mode. Vdc is equal to 3 upon 2 pi pi by 6 plus alpha 2 pi by 2 Vab d omega t and pi by 2 2 pi pi by 6 plus alpha Vac d omega t. After solving this we obtain Vdc is equal to 3 root 3 Vm upon 2 pi 1 plus cos alpha. Vdm is equal to maximum average DC output voltage. When alpha is equal to 0 the Vdc is equal to Vdm. So, normalized output is equal to Vdc upon Vdm is equal to 0.5 into bracket 1 plus cos alpha. Rms value of output voltage is calculated by using the equation V0 Rms is equal to 3 upon 2 pi and the limits of integration pi by 6 plus alpha 2 pi by 2 Vab square d omega t plus pi by 2 to pi pi by 6 plus alpha Vac square d omega t raise to half. Now, after solving this we obtain V0 Rms is equal to root 3 Vm into bracket 3 upon 4 pi in sub bracket 2 pi by 3 plus root 3 cos square alpha raise to half. Why? 3 phase semi-converter acts as a 6 pulse converter for alpha is equal to 6 less than or equal to 60 degree. If for alpha is equal to less than or equal to 60 degree for one complete cycle 6 pulses are appears across the load that is why the converter acts as a 6 pulse converter. These are the waveforms for alpha is equal to 90 degree and the mode is the discontinuous conduction mode. These are the voltage and current waveforms. Why? 3 phase semi-converter acts as a 3 pulse converter for alpha greater than 60 degree. If alpha is greater than 60 degree for one complete cycle 3 pulses are appears across the load that is why the converter acts as a 3 pulse converter. Expression for the average output voltage of 3 phase semi-converter for alpha greater than 60 degree or pi by 3 and the mode is the discontinuous conduction mode. Vdc is equal to 3 upon 2 pi limits of integration pi by 6 plus alpha to sin pi by 6 now here substitute the value of Vac Vac is equal to root 3 Vm sin omega t minus pi by 6 after solving this we obtain Vdc is equal to 3 root 3 Vm upon 2 pi 1 plus cos alpha Vdc is equal to 3 Vm upon 2 pi 1 plus cos alpha where Vm is equal to root 3 Vm is equal to maximum value of line to line supply voltage. The maximum average output voltage that occurs at del angle alpha is equal to 0 degree so Vdc max is equal to Vdm is equal to 3 root 3 Vm upon pi the normalized average output voltage is Vn is equal to Vdc upon Vdm is equal to 0.5 into bracket 1 plus cos alpha the RMS output voltage is found from V0 RMS is equal to into bracket 3 upon 2 pi limits of integration pi by 6 plus alpha to sin pi by 6 Vac square d omega t rest to half and after solving this we obtain V0 RMS is equal to root 3 Vm into bracket 3 upon 4 pi into sub bracket pi minus alpha plus sin 2 alpha upon 2 rest to half. Why this converter acts as a single quadrant converter? This converter provides the positive direction of voltage and positive direction of current that is why the converter acts as a single quadrant converter these are references. Thank you.


Hey guys, shedbear1000 here today. I'm going to be showing you how to change this alternator On this Toyota Tacoma four-cylinder stick with me. I'll show you step-by-step and tell you what tools you're going to need Okay guys and gals This is this is all you're going to need on this particular truck. This is 2004 Toyota Tacoma, I know I've said 2003 in my past videos, but they're it's the same thing It is actually the newer model It was built in 2003, but it came out after June So this truck is actually 2004, but it'll fit them It's it's pretty much the same basis on On any alternator that you're going to change but on this particular one here That's what we're going to need. You're going to need a 10 millimeter you're going to need a 12 millimeter these are boxing wrenches and you're going to need a 14 millimeter Now down to bottom on the longer bolt You may need Or you may want to use a ratchet wrench If you happen to have two 14 millimeter wrenches handy that'll work as well Just doesn't go as quick So the first thing you're going to want to do is I'm going to move these out of the way right now okay Is you're going to want to unhook your negative battery terminal? because you are going to be unhooking a Cable off of the alternator That That is constant power.  It's going to spark it may well together Now if you can try to put this negative cable down in there like that so that way it doesn't if it's up here It doesn't actually like you know bring itself over. Okay. So just push push that down there like that now We're ready to go Now I want to show you what we're going to do Up here from the top of the alternator. I'm going to try to hold you here. Let me get get you some light down here Now right down in here You want to have a plug right here on top of this plug? There's a little tab you got to squeeze that tab down and Pull your plug out now. It can be finicky and you may have to use two hands like me because I'm kind of weak on my right hand now. So we shall just Push that tab down and Pull that straight out just like that. Now like I said, it's it's the same basis on any alternator pretty much on Anything you're going to want to change your alternator on it's the same basis. You may need different tools You may have different wiring setup But like I said It's pretty much the same now. We've got this wire appears when I was telling you about the main The main charging wire because if you would try to do this and you hit something metal like that It would spark and cause a problem could start a fire.  Okay, so there's that I don't know where my cover is either supposed to be a red cover on here Okay, that you may have to pop open. I don't know where this one went to But anyway, try to just move them out of your way there. Okay now up here on the top Right Right down in here Let me get you. Let me grab a wrench right down in here. These are 12 millimeter I'm gonna be one here. You're gonna want to loosen this one. Okay. It's eventually going to come clear out Okay, but go ahead and loosen this now if you can get you know if you can fit your ratchet in there That's fine. Use your ratchet wrench whatever But we're just gonna loosen that for now Then this one we're going to loosen this because this is what tightens your your belt up. Okay, I think we're on our own Make sure you go the right way if it starts tightening it then you'll know you're going the wrong way So go ahead and loosen this bolt up This long bolt here and get that out of the way now see that belt still going to be tight because we didn't loosen the bottom bolt So let me get you down underneath here. So we can I'll show you how to Loosen the bottom. It's a longer bolt. I'll show you how to loosen that bottom bolt and take it out because it can be finicky but Don't be alarmed. It's nothing major Okay, we're down here on the bottom now. There's the bottom of the alternator right there See there's a head of the bolt That's that comes through that's 14 millimeter the same way with on the back here There's a nut. Okay. There's a 14 millimeter knot. Let me get under here right here Where are my fingers pointing right there? So what I'm going to do is I'm going to ratchet the nut off of this end and hold the other end with my Don't know if I can get you guys in here I'm going to hold the other end with my wrench so let me see if I can Maybe get you guys to see somewhat Of what I'm talking about here.  I love this ratchet extends out in case you need more more oomph So I've got this loose I should be able to turn to get where you guys can see and I can do this without getting in your way In any way you're going to take this long Take this nut off the long bolt Don't lose it This is the bolt here The bolt You're gonna pull that out. Like I said, they can be finicky You may have to get a pair of pliers of ice grips, but see now your your belt's loose If you see no alternator move Okay So can't see what I'm saying There's really more room than what it looks, but when you get a camera in here It's not as much room Keep knocking the damn camera over Just like that. Okay. Now we're going to take go back up to the top and we're going to take that top bolt out Right up there. Okay, so let's go up the top and we'll pull the old alternator out and put The new one in. Okay guys, there's really no good way to get you guys down in here, but I'm sorry about that, but I'm gonna go ahead and finish taking that bolt out here Since we already have it loose Now this alternator is still good I've explained that in other videos why I have two good ones, but since we bought a new battery I'm gonna put the one The alternator that we took back. I'm gonna put it back on here So that way if anything happens to it I can take it back, but there's your little setup there Okay, just goes like just goes like that now Just move this back and forth as you're pulling up and I'll show you why it it gets kind of stuck on there Just pull it up. I don't know if you've seen what I just did to that This line right here That'll kind of stay out of the way there for you or it should And then your alternator is going to come up here You're gonna have to finagle it. It's gonna come right up out through here. Okay, just like that That's how you get that out. All right. Like I said, this alternator is still good. So I'm gonna keep it in the toolbox Because I always have tools with me now Down in here. I'll show you down there in just a second, but You've got two ears That come up here like this Okay, and that bolt goes through there. I want you tighten that down on them ears There's like a bushing in the front one here that you may have to tap back and it'll slide in easier for you And I'll show you that right now if I can Right here See this thing actually move Back and forth. So what I'm gonna do is I'm gonna tap this back in Don't know if I can use my ratchet or not. I don't want to use my ratchet One do now is set these things side by side, you know, look them over Make sure they're the same Okay, make sure you got the same pins inside of here.  There's three in this one. There's three in that one Make sure these are the same and they are Everything looks the same. So let's go ahead and take our tag off There's your before you start You don't know much about them. Maybe you should read that so I want to slide this back down in there And we're gonna start that bottom bolt. We need to get up under here and get it started into the mount Start this in that hole. What you're gonna notice is right. You can see that's not lined up Okay So what you can do by lining that up is just move this back and forth As you're pulling down Because here's where you're gonna want to start your bolt at just like that. Okay? So what I'm gonna do is I've got to set you down. There's no way to do this I'm sorry, but I'm gonna wiggle that back and forth while I'm pushing that bolt in and once that bolt starts in that hole You'll be fine. You're ready to go. So let me do that and I'll be back with you Okay, guys, we got it through that your hardest part is getting that lined up Okay, so we got that through So I'm gonna go ahead and start my night on here.  You want to make sure you get in there the right way like let me show you some like right there That's not all the way on that belt. So make sure That you get that belt I'm perfect like that. Just like that same way. Let's check your water pump and check Down in here and make sure that belt is on correctly Start this bolt in here get it You know finger tight a little bit there now. He may have to just like that. You may have to Loosen this up a little bit if you're putting a new belt on but this one's already stretched. So there that goes So what I'm gonna do is I'm gonna snug this up a little bit and then I'm gonna tighten this up Okay, and that's what we're gonna do next with our 12 millimeter wrench Now they all they do they do make it belt. Damn it. They do make it belt gauge But always go by feel and how much reflection it has I'm sorry guys. Let me let me get back to you on this thing just just for a second. Okay. Okay guys all I did was bring Bring it until This piece barely touches that and then you're gonna want to tighten this bolt here up Like I said, you can use a ratchet on it But you don't want it to super tight in these because not only will it wear your belt out prematurely It'll wear the bearings out with that much pressure And your new alternator and you don't want that So if it's been a long time, let's say you bought a vehicle brand new. Let's say it's time for an alternator If you've never replaced the belt just go ahead and replace it no matter what it looks like Now you can always keep it in case of a you know backup And emergency throw on your trunk toolbox or whatever, but See this is what I'm looking for on this belt just some You know, I called about a half inch deflection Okay And that's that now I'm gonna go underneath And then you're gonna want to tighten this bolt up This one here Then you're gonna want to go underneath and tighten your big one And then we'll I'm gonna do that and I'll come back and I'm gonna hook. I'll show you how to hook it back up Okay, now we're just gonna take our plug There's only one way it can go so you can't mix it up But that that tab will go on the top on this particular model Push it in till you hear it click give it a little tug make sure it's It's good and snug on there and take your your wire and put on there Your nut and again these you don't want to be super tight, but you just want it snug Just so it doesn't come loose Because you'll strip it or twist the wire off inside. So there you go. That's good enough Now that's all there is to that Now that's done Now let's put our battery terminal in back on here Tighten it up Just like I showed you guys in the past if you follow these I know you can't really hardly see much down under there But I did the best I could guys Okay, so there's that now we're going to start it up And make sure there's nothing arcing and sparking and if you had a If your battery light was on before you might want to you know check make sure it's out Of course, we didn't have that problem. I guess fuel pump we put on here back in January. I think it was I think it's going bad Okay, see the battery lights out which always was never on but just for instance If you've got the gauge make sure the gauge is charging good your amp gauge your voltage you want not now You have to reset your clock and your radio and all that stuff, but let's go out here. Make sure The belt spinning like it should make sure there's no arcing and sparking quiet Okay, everything looks good. So there you go fairly simple on this one some of them are really hard to get to On different on different vehicles, but this one wasn't too bad Final check make sure it didn't leave any tools or any bolts or anything laying around there Check underneath when you get done and there you go I know it looks a little difficult because of the trouble I was having but that's just because the camera was in my way This particular truck is fairly easy to do The hardest parts line in that alternator up, you know in between the ears on that on that bottom mount, but Yeah, it's this one here is one of the easiest ones other than an older Chevy when they were right on top So just follow these instructions the best you can and you should be okay So thanks for watching guys appreciate it. Shea Berry the myth man alleged. I'm gone for now We'll see you soon