DC Motors Which of the following motor is preferred for operation in highly explosive atmosphere? Air motor Battery operated motor Shunt motor Series motor Air motor Battery operated motor Shunt motor Series motor ANSWER DOWNLOAD EXAMIANS APP
DC Motors The mechanical power developed in a dc motor is maximum when back emf is equal to _____ the applied voltage. Half None of the listed here One-third Twice Half None of the listed here One-third Twice ANSWER DOWNLOAD EXAMIANS APP
DC Motors The speed of a motor falls from 1100 r.p.m. at no-load to 1050 r.p.m. at rated load. The speed regulation of the motor is 6.77% 4.76% 2.22% 8.85% 6.77% 4.76% 2.22% 8.85% ANSWER DOWNLOAD EXAMIANS APP
DC Motors The main disadvantage of the Ward-Leonard control method is Low efficiency at high loads All of these High maintenance cost High initial cost Low efficiency at high loads All of these High maintenance cost High initial cost ANSWER DOWNLOAD EXAMIANS APP
DC Motors Excessive sparking at brushes may be caused due to Worn bearings Loose coupling Misaligment of machine Dirt on the commutator Worn bearings Loose coupling Misaligment of machine Dirt on the commutator ANSWER DOWNLOAD EXAMIANS APP
DC Motors If the speed of a dc shunt motor is increased the back emf of the motor will Become zero Decrease Increase Remains same Become zero Decrease Increase Remains same ANSWER DOWNLOAD EXAMIANS APP