A decrease in the field current of a synchronous motor results in: O A. Power factor of the machine will increase O B. Decreasing the induced voltage; motor will absorb more reactive power O C. No change in the induced voltage O D. Increasing the induced voltage; motor will absorb more reactive power O E. None of the other choices are correct

A decrease in the field current of a synchronous motor results in: O A. Power factor of the machine will increase O B. Decreasing the induced voltage; motor will absorb more reactive power O C. No change in the induced voltage O D. Increasing the induced voltage; motor will absorb more reactive power O E. None of the other choices are correct

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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Similar questions

Which one of the following statements is not correct about synchronous machine Select one: O a. The rotor dc current is required only for synchronous generator O b. The induced voltage in the stator depends on the rotor dc current O. The resistance of the stator windings can be neglected compared with the value of the synchronous reactance If the synchronous motor is overexcited, then: Select one: O a. The motor will absorb reactive power to the source. O b. The motor will operate at unity power factor. O c. The motor will deliver reactive power to the source. O d. The motor will deliver real power to the source.
An increase in the torque angle a results in: O A. No change in the induced torque O B. Decreasing the induced torque O C. Decreasing the load on the synchronous motor D. None of the other choices are correct O E. Increasing the induced totque
23. When the circuit breaker is always tripping, most likely There is an overloading c. The supply line are open a. b. There is an over current d. The load is removed 24. The synchronous motor is not inherently self- starting because the rotating magnetic field does not have enough poles b. the rotating magnetic field is produced by only 50 HZ frequency currents the force required to accelerate the rotor is to the synchronous speed in an instant is d. the starting devices to accelerate the rotor to near synchronous speed is absent 25. Synchronous motor has speed a. slight drop in speed on full load b.high speed at low torque а. с. c. constant speed d. low speed at high -
9. The synchronous speed of a three-Phase induction motor depends on the number of magnetic poles in the machine and the actual speed of rotation the actual speed of rotation and the applied Voltage in RMS the actual speed of rotation and number of magnetic poles intensity on the rotating magnetic field and the applied Voltage in RMS frequency of the applied voltage and the number of magnetic poles in the machine
4. What for brushes are employed in DC generator? 5. What is the function of armature in a DC generator? 6. What is the function of commutator in a DC machine in generator action. 7 Whieh diffe u0ad in
The prime mover driving SG is lost, but the machine remains connected to the large power system and the field supply also remains on. The machine will: Select one: a. get burnt b. behave as a Synchronous Generator with no change c.behave as a synchronous motor and rotate in the same direction d. behave as a synchronous motor but rotate in a reversely
In a synchronous motor, a decrease in the torque angle a results in: O A. No change in the induced torque O B. Increasing the induced totque; motor will speed up O C. Decreasing the load on the synchronous motor O D. None of the other choices are correct O E. Decreasing the induced torque; motor will slow down
estion 1 "A DC machine consists of 4-poles and operating at 1500 rpm. Its frequency of the induced emf in armature is determined as 50 Hz" O True O False S A Moving to another question will save this response. e IT:P AR
26. A 4-pole, 50 Hz induction motor operates at 5% slip. The frequency of e.m.f. induced in the rotor will be .... (1) 25 Hz (iii) 2.5 Hz (ii) 50 Hz (iv) none of the above
Q2. Suppose that a synchronous generator is connected to an infinite bus. Base frequency of the system is 50 Hz, the voltage of the infinite bus is 1.03 pu, the voltage of the machine is 1.01 pu, the rotor angle under equilibrium is 37.5°, the equivalent line reactance is 0.2945 pu. Find the oscillation frequency of the machine if it is subjected to small disturbances. (Take H=2.1) the voltage of the infinite bus is 1.03 pu voltage of the machine is 1.01 pu rotor angle under equilibrium is 37.5° equivalent line reactance is 0.2945 pu Take H=2.1 Base frequency of the system is 50 Hz You need to take these values into account with formulas.
A DC motor should be operated in a strong field which is due to the What happens to if suddenly goes a) nothing, it continues rotating b) it over speeds c) it stops rotating current if moter if rotating to zero. as before
A synchronous machine is a three-phase, two-pole machine with 36 stator slots and 5/6 full-pitched balanced armature windings. Each phase winding is made up of eight identical coils connected in sequence. Balanced three-phase 66 Hz currents with a peak amplitude of 16 A are used to drive the stator phases. a) What is the basic stator space mmf's maximum amplitude? (A.turns) b) How fast does the fundamental stator space mmf rotate mechanically? (rpm) c) What is the third-harmonic stator space mmf's maximum amplitude? (A.turns) d) What is the fifth-harmonic stator space mmf's maximum amplitude? (A.turns) e) How fast does the fifth-harmonic stator space mmf rotate mechanically? (rpm)