Problem: A separately excited dc motor has the following parameters: machine constant 5, flux under the poles 0.35 Vs, armature resistance 0.22Ω, rotational losses 250 W, field losses 150 W. The armature voltage is 230 V.

Calculate the following:

1. The speed of the motor if the motor supplies zero torque to the load.

2. The speed of the motor, the armature current, and the power efficiency if the motor supplies 35 Nm of torque to the load.

3. The new armature voltage in order to maintain a speed of 1200 rpm under a 35 Nm supplied torque.