Answer Happy

Problem 1. (20 pts) Induction Motors 1. The s is the slip and Ns is the synchronous speed, then the actual running speed of the motor will be -(a) Ns (b) s.N, (C) (1-5)Ns (d) (Ns-l)s 2. The efficiency of the induction motor is? (a) 60 to 90% (b) 80 to 90% -(c) 95 to 98% (d) 99% 3. In the squirrel-cage induction motor, the number of slip rings is usually? (a) two .(b) three (c) four (d) none 4. In a squirrel-cage induction motor, the starting torque is usually? (a) low (b) negligible (c) same as full-load torque (d) slightly more than full-load torque 5. The Star-delta starting of motors is not usually applicable in case of? (a) single-phase motors (b) variable speed motors (c) low horsepower motors (d) high-speed motors 6. An induction motor is also called as? .(a) D.C. compound motor -(b) D.C. series motor (c) synchronous motor (d) asynchronous motor