A 180kW, 230V, 435 rpm dc shunt motor has a nominal full-load current of 860A. (a) Calculate the total losses and efficiency at full load and rated speed. (b) Find the shunt field exciting current if...

Extracted text: A 180kW, 230V, 435 rpm dc shunt motor has a nominal full-load current of 860A. (a) Calculate the total losses and efficiency at full load and rated speed. (b) Find the shunt field exciting current if the shunt field causes 20% of the total losses. (c) Calculate the value of the armature resistance and the back emf, if 50% of the total losses at full-load are attributable to the armature resistance. [ (d) Find the field current to make the motor run at 1000 rpm under no load. [C (e) Identify the motor efficiency if it is operating at half rated current at 1000 rpm. Assume that mechanical losses are linearly proportional to speed. [C