Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Textbook Question
Chapter 42, Problem 8SQ
Approximately how much time (in terms of electrical cycles) elapses from the moment the PFR opens to the moment the motor actually synchronizes?
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Chapter 42 Solutions
Electric Motor Control
Ch. 42 - What are the two basic methods of automatically...Ch. 42 - What is an out-of-step relay?Ch. 42 - Why is an out-of-step relay used on automatic...Ch. 42 - Under what conditions will the out-of-step relay...Ch. 42 - What is the last control contact that closes on a...Ch. 42 - What influence do both of the polarized field...Ch. 42 - Prob. 7SQCh. 42 - Approximately how much time (in terms of...Ch. 42 - How does the AC coil of the PFR receive the...Ch. 42 - Why is a control relay (CR1) used in Figure 426?...
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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
- What assurance is there that the rotor will lock into step at the synchronous speed with the use of a timing relay?arrow_forwardIf the motor fails to achieve synchronous operation, what action is necessary?arrow_forward1. Explain briefly in one(1) sentence what is the function of the squirrel cage winding inthe operation of the synchronous motor.(for 50 points)arrow_forward
- Determine the time of operation for an IDMT overcurrent relay having TSD=0. 6, I_Load=80A, I_Threshold=3A, Index=1.5.Place very inverse and inverse time relay in the following series of curves. Please answer in short i will likearrow_forwardExplain in details why does the rotor of the three phase induction motor rotate, then determine the speed of the revolving field relative to i) stator field distribution ii) rotor structure.arrow_forward• T or F, modify the wrong part if False, please underline twice your answer if True or False. Since electrical machines are made up of coils, a synchronous motor can only operate at lagging power factor.arrow_forward
- After a synchronous motor has reached the synchronizing speed, the best time to apply the field current is when the A. induced field current is increasing to a maximum value.B. south stator poles are opposite the south rotor poles.C. rotor poles are traveling faster than the stator poles.D. north rotor poles are directly opposite the south stator poles.arrow_forwardThe factor that enables the synchronous motor to operate at different electrical load characteristics Please explain.arrow_forwardHow are a PSC motor and a capacitor-start-capacitor-run motor similar? Select one: A. BOTH USE A STARTING CAPACITOR B. BOTH USE A RUNNING CAPACITOR C. BOTH USE STARTING RELAYS D. NONE OF THE ABOVEarrow_forward
- is the following correct? True or false? In order to change the rotation direction of the asynchronous motor, any two of the 3 phases applied to the stator can be swapped.arrow_forwardWhat kind of current does a synchronous motor with an excessively increased excitation current draw from the network? a) apparent current b) capacitive current c) inductive current d) ohmic currentarrow_forward
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