Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Textbook Question
Chapter 39, Problem 10SQ
The speed of a synchronous motor is fixed by the
- a. rotor winding.
- b. amortisseur winding.
- c. supply voltage.
- d. frequency of power supply and number of poles.
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Students have asked these similar questions
1. The operation of Commutator in DC Motor is *
O a) to convert dc to ac
O b) to convert ac to dc
O c) to convert fixed dc to variable dc
O reverse the current direction in the rotating windings each half turn
How rotor winding is derived the power in the
three-phase induction motor?
O a. from Single phase supply
O b. from stator winding
O c. None of the above
O d. from slots
Which of the following statements about three-phase induction motor is false
(A) The speed of rotation of the magnetic field is called the synchronous speed.
(B) A three-phase supply connected to the rator produces a rotation magnetic field.
(C)The rotating magnetic field has a constant speed and constant magnitude.
(D) It is essentially a constant speed type machine.
Chapter 39 Solutions
Electric Motor Control
Ch. 39 - Prob. 1SQCh. 39 - What is the effect of the starting winding of the...Ch. 39 - What are typical applications of synchronous...Ch. 39 - Prob. 4SQCh. 39 - A loaded synchronous motor cannot operate...Ch. 39 - Why must a discharge resistor be connected in the...Ch. 39 - Depending on their power factor ratings, what is...Ch. 39 - At what power factor do incandescent lights...Ch. 39 - Prob. 9SQCh. 39 - The speed of a synchronous motor is fixed by the...
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- T-a. The direction of rotation of a single-phase split-phase motor can be change by........ a) reversing the connection of the start winding b) reversing the connection of the run winding c) reversing the connection of the start and run winding at the same time d) "a" or "b", not "c" T-b. Single-phase split-phase motors using an electrolytic capacitor in the start winding circuit should not be cycled more than about__________ time per hour. a) 8 b) 12 c) 24 d) none of the above T-c. When replacing the capacitor in a capacitor-start induction-run motor, one must be sure to replace the bad capacitor with__________ . a) a smaller one b) one of the same size c) a larger one d) none of the abovearrow_forwardThe frequency of induction motor is 50 Hz and the slip is 2.5% then frequency of rotor current is a. 1 Hz b. 1.2 HZ c. 1.25 HZ d. 1.5 HZarrow_forward6- Which of the following supply is given to the rotor winding of 3-Phase Induction Motor: a) DC Supply b) AC Supply c) No Supply d) Pulsating Supply 7- 3-Phase Induction Motor will have Starting Torque and Starting Current a) High, High b) Low, Low. c) High, Low d) Low, High 8- Which of the following method is used for controlling the speed of an induction motor: a) Changing number of stator poles b) Supply voltage control c) Frequency control d) All the options are correct 9- Which of the following method cannot be used for starting of 3-Phase Squirrel Induction Motor: a) Star-Delta Starting b) Line resistor startling c) transformer Starter d) Rotor Resistance Starting 10- The rotor of a stepper motor has no: a) windings b) commutator c) brushes d) all of the abovearrow_forward
- 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 -arrow_forwardThe rotor resistance and standstill reactance of a 3-phase induction motor are 0.015 Q and reactance 0.09 0 per phase. (i) What is the p.f. of the motor at start? (ii) What is the p.f. at a slip of 4 per cent? (iii) If the number of poles is 4, the supply frequency is 50-Hz and the standstill e.m.f. per rotor phase is 110 V, find out the full-load torque. Take the full-load slip as 4 per cent.arrow_forward9. 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 machinearrow_forward
- The rotor of a 3-phase, 60-Hz, 4-pole induction motor gets a total of 120kW through the air gap with a rotor frequency of 3Hz. a. What is the rotor speed (RPM)? b. What is the rotor copper loss (W)?arrow_forwardthe magnetic strengh of the field poles on a perment magnet DC motor cannot be varied a- true b- falsearrow_forward4-What is the main function of a diverter used in series wound DC motor? 5- What is the main difference between (iron and friction losses) and copper (Cu) losses in DC generators? 05arrow_forward
- If the power measured per phase is increasing, what will happen to the speed of the three phase induction motor? a. Decrease b. Equal c. Increase d. Zeroarrow_forward(6) The air gap power of 440 V, 50 HZ 6 pole 3- phase induction motor is 100 KW. The rotor frequency is 1.3 HZ. Find rotor copper losses per phase.arrow_forwardThe supply frequency to the stator of an 8-pole induction motor is 70 Hz, and the rotor frequency is 6 Hz. Determine the slip and the rotor speed.arrow_forward
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