A permanent magnet DC motor is being considered for use as a drive motor for a vehicle. The motor is known to have the following properties

No load speed @ 100 V = 2000 rpm torque at 20 A = 10 Nm R = 0.5 Ω

a) What is the full load (10 Nm) speed when the machine runs with the rated voltage of 100 V?

b) What terminal voltage V is needed to provide the cruising speed requirement of 2500 rpm with a torque of 10 Nm?

c) What terminal voltage V is needed to provide a braking torque of 10 Nm at zero speed ?

d) If the armature of this machine were short circuited (V = 0), what would be the current and torque if it was driven at 1000 rpm by the moving vehicle.