Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Textbook Question
Chapter 39, Problem 11SQ
Varying the DC voltage to the rotor field changes the
- a. motor speed.
- b. power factor.
- c. phase excitation.
- d. slip.
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what is the conclusion for the concepts of rotating amature and rotating field in an alternator?
8. A 3-phase induction motor is running at 2%
slip. If the input to rotor is 1000 W, then
mechanical power developed by the motor
is ............
(i) 20 W
(iii) 500 W
(ii) 980 W
(iv) 200 W
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
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
- How voltage is built up in dc shunt generatorarrow_forward3.An induction motor has a rotor resistance and reactance at standstill of 0.1 ohm and 3.5 ohm respectively. At standstill the voltage induced to the rotor is 60volts per phase. If the slip is 5%, determine the rotor currentarrow_forwardDescribe the similarities in the construction of a DC motor and a DC generator. Please answer in short point wise and dont copy from other sources i will like ltarrow_forward
- 6- 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_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_forwardA DC shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field resistances are 0.01 2 and 44N respectively. The stray losses are 375 W. What is percentage efficiency of the DC generatorarrow_forward
- 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 inarrow_forwardQ. Excited DC motor.arrow_forwardWhat are the different ways to supply DC power to rotor of an alternator? Which method is superior and why?arrow_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_forwardQ1) Under what condition will an induction motor work as an induction generator?arrow_forwardWhich 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.arrow_forward
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Single Phase Induction Motor, How it works ?; Author: Lesics;https://www.youtube.com/watch?v=awrUxv7B-a8;License: Standard Youtube License