Chose the correct answer: 1- A squirrel cage induction motor is not selected when (A) initial cost is the main consideration (B) maintenance cost is to be kept low (C) higher starting torque is the main consideration (D) all above considerations are involved 2- The torque of an induction motor is (A) directly proportional to slip. (B) inversely proportional to slip www. (C) proportional to the square of the slip (D) none of the above 3- Insertion of resistance in the stator of an induction motor (A) increases the load torque (B) decreases the starting torque (C) increases the starting torque (D) none of above 4- Increase in the length of air-gap in the induction motor results in the increasing of its (B) magnetizing current (C) speed (D) power factor (A) air-gap flux 5- In cumulatively cascade method for speed controlling, if PA is the number of poles of main motor and PB is the number of poles of auxiliary motor. Then the speed of the set is given by (A) 120f/PA + PB (B) 120f/ PA - PB (C) 120f/ PA (D) 120f/PB 6- The leakage reactance of an alternator is determined by performing. (A) open-circuit and zero power factor tests (B) zero power factor and slip tests short-circuit tests (D) short-circuit and slip tests 7- The short-circuit characteristic of an alternator is ......... (D) none of above ******* (C) open-circuit and (A) always linear (B) always nonlinear (C) either of (A) or (B) 8- In alternators, the distribution factor is defined as the ratio of emfs of. (A) distributed winding to concentrated winding (B) full pitch winding to distributed winding (C) distributed winding to full pitch winding (D) concentrated winding to distributed winding 9-Zero power factor method of an alternator is used to find its (A) field resistance (B) armature resistance (C) efficiency (D) voltage regulation 10- Synchronous condenser is (A) overexcited synchronous motor with no mechanical load (B) over excited synchronous motor with mechanical load (C) under excited synchronous motor with no mechanical load (D) normal excited synchronous motor with no mechanical load

Chose the correct answer: 1- A squirrel cage induction motor is not selected when (A) initial cost is the main consideration (B) maintenance cost is to be kept low (C) higher starting torque is the main consideration (D) all above considerations are involved 2- The torque of an induction motor is (A) directly proportional to slip. (B) inversely proportional to slip www. (C) proportional to the square of the slip (D) none of the above 3- Insertion of resistance in the stator of an induction motor (A) increases the load torque (B) decreases the starting torque (C) increases the starting torque (D) none of above 4- Increase in the length of air-gap in the induction motor results in the increasing of its (B) magnetizing current (C) speed (D) power factor (A) air-gap flux 5- In cumulatively cascade method for speed controlling, if PA is the number of poles of main motor and PB is the number of poles of auxiliary motor. Then the speed of the set is given by (A) 120f/PA + PB (B) 120f/ PA - PB (C) 120f/ PA (D) 120f/PB 6- The leakage reactance of an alternator is determined by performing. (A) open-circuit and zero power factor tests (B) zero power factor and slip tests short-circuit tests (D) short-circuit and slip tests 7- The short-circuit characteristic of an alternator is ......... (D) none of above ******* (C) open-circuit and (A) always linear (B) always nonlinear (C) either of (A) or (B) 8- In alternators, the distribution factor is defined as the ratio of emfs of. (A) distributed winding to concentrated winding (B) full pitch winding to distributed winding (C) distributed winding to full pitch winding (D) concentrated winding to distributed winding 9-Zero power factor method of an alternator is used to find its (A) field resistance (B) armature resistance (C) efficiency (D) voltage regulation 10- Synchronous condenser is (A) overexcited synchronous motor with no mechanical load (B) over excited synchronous motor with mechanical load (C) under excited synchronous motor with no mechanical load (D) normal excited synchronous motor with no mechanical load

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter32: Three-phase Motors

Section: Chapter Questions

Problem 6RQ: Name three factors that determine the torque produced by an induction motor.

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