Electrical Machines A smaller air gap in a polyphase induction motor helps to reduce the chance of cogging. increase the starting torque. reduce the chance of crawling. reduce the magnetizing current. reduce the chance of cogging. increase the starting torque. reduce the chance of crawling. reduce the magnetizing current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole dynamo with wave wound armature has 51 slots contains 20 conductors in each slot. If induced emf 357 Volts and speed is 8500 rpm, flux per pole will be 1.4 mWb. 1.2 mWb. 2.7 mWb. 3.5 mWb. 1.4 mWb. 1.2 mWb. 2.7 mWb. 3.5 mWb. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Lap winding is prefered for which type of machines? high current and high voltage low current and high voltage high current and low voltage low current and low voltage high current and high voltage low current and high voltage high current and low voltage low current and low voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The 3 - Φ induction motor with rotor circuit open will get over heated. run normally. not run. make noise. get over heated. run normally. not run. make noise. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 2 and 3 3 only 1, 3 1, 2, 3 and 4 1, 2 and 3 3 only 1, 3 1, 2, 3 and 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines How can the synchronous speed of a 3 - Φ IM be varied? By varying supply voltage. By varying number of poles. Both (A) and (B). By varying the supply frequency. By varying supply voltage. By varying number of poles. Both (A) and (B). By varying the supply frequency. ANSWER DOWNLOAD EXAMIANS APP
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