Section 5: Choose the correct AnswerWhat happens if field winding of the synchronous motor is short* circuitedFirst, starts as induction motor then run as synchronous motorNot startMotor will burn outRun as induction motori da - When the field of a synchronous motor is over excited, the power factorwill beLeading OLaggingZeroUnityThe synchronous motors are not self-starting becauseThe direction of torque on the rotor reverses after every half cycle. OSlip is not present in synchronous machineStarting winding is not present in the synchronous machineDC excitation is used

Answered: Image /qna-images/answer/3ebc4035-3348-4cb4-8952-411996db8e0b.jpg

Section 5: Choose the correct Answer لیس ان What happens if field winding of the synchronous motor is short * circuited First, starts as induction motor then run as synchronous motor Not start Motor will burn out Run as induction motor e- When the field of a synchronous motor is over excited, the power factor will be Leading Lagging O Zero Unity ليس هد The synchronous motors are not self-starting because

Section 5: Choose the correct Answer لیس ان What happens if field winding of the synchronous motor is short * circuited First, starts as induction motor then run as synchronous motor Not start Motor will burn out Run as induction motor e- When the field of a synchronous motor is over excited, the power factor will be Leading Lagging O Zero Unity ليس هد The synchronous motors are not self-starting because

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter35: Harmonics 916

Section: Chapter Questions

Problem 3RQ: Would a positive-rotating harmonic or a negative-rotating harmonic be more harmful to an induction...

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K-1)The speed of a 3-phase wound-rotor induction motor can be changed by varying the amount of resistance in the rotor circuit. a) true b) false K-2). Which of the following statements are true about a 3-phase synchronous motor? a) It is a constant speed motor even under varying loads. b) It runs at the same speed the magnetic field rotates on the stator. c) It can correct its own, and the supply line's power factor d) all of the above K-3. A) What determines the speed of a 3-phase synchronous motor? a) the number of poles b) the frequency of the supply c) both "a" and "b" d) neither "a" nor "b" K-3)B) From a technician's standpoint, which of the following is the most practical method of providing a wide range of speed control for a 3-phase synchronous motor? a) by changing the frequency b) by changing the number of poles c) both "a" and "b" d) neither "a" nor "b"
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Type your question here The rotor of a 4 pole, 50 Hz, slip ring induction motor has a resistance of 0.25 ohm per phase and runs at 1440 rpm at full-load. Calculate the extemal resistance per phase, which must be added to lower the speed to 1200 rpm, torque remaining the same?
Would a positive-rotating harmonic or a negative-rotating harmonic be more harmful to an induction motor? Explain your answer.
What do you mean by 'static', 'alternating’, and 'rotating' magnetic field? Explain the significances of the rotating magnetic field in rotary machines. What are the purposes of using starter in a three-phase induction motor? With neat diagrams, explain the operation of a Wye-Delta starter for a three phase induction motor.
What is the answer for Question 7
1-why the slipoccur in the induction motor? 2- why the slip is less than 1? 3-what the adrantage of study the slip in the induction motor?
4. Why Induction motors are extensively used these days:
When a cumulatively compounded long shunt DC motor is run as a generator, it will operate also as a cumulatively compounded generator. * True O False A DC series motor can be started without load. * O True O False
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Explain in detail the braking of Induction Motors