Simplest DC Motor Speed Controller Circuit Diagram
The effect can be eliminated by means of Ri compensation, which essentially entails measuring the motor’s current consumption, relating this to the motor’s instantaneous drop i across Ri, and increasing the supply voltage accordingly. The load current is measured as the drop across sensing resistor R3. For optimum results, this impedance must be kept about equal to that of the motor. Figure 2 shows the practical circuit of the motor driver based on a power operational amplifier . Simple DC operated motors with a permanent magnetic stator behave as an independently energized motor. The speed of an ideal motor with an, infinitely low internal resistance is in direct proportion to the voltage applied, irrespective of the torque. The motor thus runs at a speed at which its reverse electromotive force (e.m.f.) equals the supply voltage. The reverse e.m.f. is directly proportional to the force of the (constant) magnetic field , and the motor speed. In theory, therefore, the motor speed can...