Question

Answer True or False for each statement.

Item 1 (20 pts) True False IM is the most popular electric motor machine Squirrel cage IM are quite flexible for torque control The IM DC test can be carried out similarly regardless of stator winding connection (A or Y) For fan/pump applications the starting torque is an important parameter Maximum torque depends on Rotor resistance Adequate starting torque for squirrel-cage motors can be obtained by inserting Resistors in its rotor Slip for Maximum torque does not depend on motor reactances Rotor iron losses decrease with motor speed Rotational power, Prot [Watts], decreases with motor speed Mechanical losses increases with motor speed

Answer 1

IM is the most popular electric motor machine - True Squirrel cage IM are quite flexible for torque control - True The IM DC test can be carried out similarly regardless of stater winding connection (Delta or Y) - For fan/pump applications the starting torque is an important parameter - False Maximum torque depends on Rotor resistance - True Adequate starting torque for squirrel-cage motors can be obtained by inserting Resistors in its rotor - Slip for Maximum torque does not depend on motor reactances - s_m = R_2/X_2 Therefore s_m proportional to 1/X_2 so it depends on Reactance (False) Rotor iron losses decrease with motor speed - False Rotational power, Prot [Watts), decreases with motor speed - False Mechanical losses increases with motor speed - True {Because P_mesh logs proportional to N^3}.