DC Controls

In order to understand how a DC control works, basic working knowledge of a DC motor is required. A simple DC motor works on the principle that when a current carrying conductor is placed in a magnetic field, it experiences a mechanical force. In a practical DC motor, the armature is the current carrying the conductor, and the field provides magnetic field. Most DC motors today are constructed using a permanent magnet field hence, referred to as a PM DC motor.

Based on the motor construction and Faraday and Lenz laws of physics, the motor speed is 1) directly proportional to supply voltage. 2) inversely proportional to armature voltage drop. 3) inversely proportional to the flux due to the field findings. Thus, the speed of a DC motor can be controlled in three ways: by varying the supply voltage, varying the flux, and by varying the current through field winding, By varying the armature voltage, and by varying the armature resistance.

In most cases the voltage control method is the most economical and easily produced and used. To accomplish this voltage change several electronic designs are used, Triac, SCR and PWM, all having their own benefits and weaknesses.

Since most fractional and integral horsepower DC motors are available from 12VDC through 180VDC, there are a great many drives available, each specifically suited for the application.

If you would like to have us prepare a competitive quote on DC controls, please contact one of our sales representatives or contact our office directly at (949) 369-8000.