A 500V shunt dc motor has a nominal armature current of 40A, and operates at 1200 rpm. if the armature resistance is 0.25 (ohm), calculate:
1. The counter emf
2. The power loss
3. The developed torque.
4. The starting current, if the motor is directly connected to the 500V supply
5. The valve of a starting resistor limiting the initial armature current to 60A