Question

A permanent magnet DC motor has an armature resistance of 0.5 Ω and when a voltage of 120 V is applied to the motor it reaches a steady‐state speed of rotation of 20rev/s and draws 40A. What will be:

(a) the power input to the motor?
(b) the power loss in the armature?
(c) the torque generated at that speed?

Answer 1

12 N-m

Step-by-step explanation:

The dc motor is operating at 24 V that is its terminal voltage V =24 V

Armature resistance = 0.2 ohm

No load speed = 240 radian /sec

For motor we know that as the motor is on no load so so

Power developed in the motor

Now we know that power = torque× angular speed

So