B2. (a) What would be the effect of armature reaction on D.C. machines? (4 marks) Suggest one method of reducing armatur
Posted: Mon May 09, 2022 7:51 am
B2. (a) What would be the effect of armature reaction on D.C. machines? (4 marks) Suggest one method of reducing armature reaction on operation. (b) The armature resistance and field resistance of a shunt D.C. motor are 0.15 and 105 respectively. The motor is connected to the supply voltage of 240 V D.C. and draws an armature current of 240 A at a torque of 200 Nm. If the rotational power loss is 1 kW, evaluate (0) the back e.m.f., (ii) the motor speed in rev/min, (iii) the total losses of the motor, (iv) the input power of the motor, (v) the efficiency of the motor, and (vi) the motor speed in rev/min at one-third torque. (2 marks) (3 marks) (4 marks) (2 marks) (2 marks) (3 marks)