Electrical Machines In case of induction motors the ratio of length to pole pitch for minimum cost, is taken as 3 to 5. 1.0. 1.5 to 2. 2 to 3. 3 to 5. 1.0. 1.5 to 2. 2 to 3. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4 pole DC generator rotates at 1500 rpm. How many times in a second, will the emf induced in each armature conductor changes its direction? 750. 100. 200. 500. 750. 100. 200. 500. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines As compared to an induction motor, the air gap in a DC motor is between 50% and 90%. same. less than 50%. more. between 50% and 90%. same. less than 50%. more. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines How can the synchronous speed of a 3 - Φ IM be varied? Both (A) and (B). By varying supply voltage. By varying number of poles. By varying the supply frequency. Both (A) and (B). By varying supply voltage. By varying number of poles. By varying the supply frequency. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Flashing of DC generator means None of these creation of residual magnetism by a DC source. increasing flux density by providing extra ampere-turns in field. neutralization of residual magnetism. None of these creation of residual magnetism by a DC source. increasing flux density by providing extra ampere-turns in field. neutralization of residual magnetism. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A large series motor is never started without some mechanical load on it because otherwise it will produce sparking at brushes. draw too much current. open fuse or circuit breaker. develop excessive speed and damage itself. produce sparking at brushes. draw too much current. open fuse or circuit breaker. develop excessive speed and damage itself. ANSWER DOWNLOAD EXAMIANS APP
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