(13) For a certain polyphase induction motor, which at full load operates at its maximum power factor, the starting current and the no-load current at full voltage reduction in voltage which would just permit stable operation at a torque not exceeding the full-load value. What would be the power factor and slip at full-load Assuming the rotor and stator copper losses are equal, determine the percentage are in the ratio of 10/1 and the power factor in each case is 0:25. torque with the voltage thu

(13) For a certain polyphase induction motor, which at full load operates at its maximum power factor, the starting current and the no-load current at full voltage reduction in voltage which would just permit stable operation at a torque not exceeding the full-load value. What would be the power factor and slip at full-load Assuming the rotor and stator copper losses are equal, determine the percentage are in the ratio of 10/1 and the power factor in each case is 0:25. torque with the voltage thu

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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Name three factors that determine the torque produced by an induction motor.
1- To control the speed of an induction motor, the supply frequency is reduced by 10%. For the same magnetizing current to remain constant, the supply voltage must be....... a) Reduced by 10%, b) Reduced by 20%, c) Increased by 10%, d) Increased by 20% 2. When maximum starting torqua ic ohtoinod
An 3-phase induction motor(IM) has full load slip = 0.5%. If the rotor circuit resistance is increased so that R2new =2R2old, then the slip at which the motor develops the same full load torque is=.. * ......
8. Homework: I. What is the effect of load on the efficiency of an induction motor? I. Explain the term air-gap power or power developed in the rotor and shaft power. How these terms are related to each other? III. Derive an expression for the rotor copper loss in terms of slip and input to the rotor? What are the various losses in an induction motor? On what IV. factors do they depend? V. List the different types of stray load losses in an induction motor.
Torque-speed characteristics for three phase induction motor 4. Discuss the following (rated torque, starting torque, break down torque).
1. Explain the term air-gap power or power developed in the rotor and shaft power. How these terms are related to each other?2. Derive an expression for the rotor copper loss in terms of slip and input to the rotor?3. What are the various losses in an induction motor? On what factors do they depend?4. List the different types of stray load losses in an induction motor.
23. As load is increased from no load to full load on a 3-phase squirrel-cage induction motor, what happens to the ..
I.What is the effect of load on the efficiency of an induction motor? II. Explain the term air-gap power or power developed in the rotor and shaft power. How these terms are related to each other? III. Derive an expression for the rotor copper loss in terms of slip and input to the rotor? IV. What are the various losses in an induction motor? On what factors do they depend? V. List the different types of stray load losses in an induction motor.
1.why the slip of induction motor is never zero, 2.what happens if the slip of induction motor is one, 3.what is the value of the slip for an induction motor at on load and full load
I. What is the effect of load on the efficiency of an induction motor? I. Explain the term air-gap power or power developed in the rotor and shaft power. How these terms are related to each other? II. Derive an expression for the rotor copper loss in terms of slip and input to the rotor? What are the various losses in an induction motor? On what IV. factors do they depend? V. List the different types of stray load losses in an induction motor.
5. (a) What would be the effect on the speed-torque characteristics of an induction motor produced by: (i) halving the applied voltage with normal frequency (ii) halving both the applied voltage and frequency Also, draw and explain the speed- torque characteristics of three phase induction motor.6
1. 2. 4. 4. •.. .... ..... .... E.g. • 2. A 3 phase, 460 V, 10hp, 60 Hz, four-pole induction machine delivers rated output power at a slip of 0.05. determine the a. Synchronous speed and motor speed b. speed of the rotating air gad field c. frequency of the rotor circuit d. Slip in rpm e. Speed of the rotor field relative to the i. rotor structure ii. Stator structure iii Stator rotating field f. haft torque of this motor at the rated load? ... .... Equivalent Circuit • The induction motor consists of a two magnetically connected systems: Stator and rotor • This is similar to a transformer that also has two magnetically connected systems: primary and secondary windings. • The induction motor is similar to the transformer with the excention that its secondarv windings are free to.