8. Describe, in detail, how torque is developed in an induction motor, 9. What is slip in an induction motor and how does it vary during the normal operation of the motor? ( 10. How does current flow in the rotor of an induction motor and how and why does the frequency of that current vary? 11. Why is it harder for a synchronous motor to start spinning than an induction motor? Provide details and be specific!

8. Describe, in detail, how torque is developed in an induction motor, 9. What is slip in an induction motor and how does it vary during the normal operation of the motor? ( 10. How does current flow in the rotor of an induction motor and how and why does the frequency of that current vary? 11. Why is it harder for a synchronous motor to start spinning than an induction motor? Provide details and be specific!

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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Similar questions

Name three factors that determine the torque produced by an induction motor.
1. What is the formula for torque production in a single-phase induction motor? Draw a vector diagram for capacitor start single-phase induction motor.2. Which type of starter is popular for using in induction motor and why?
A three-phase induction motor, operating at rated voltage and frequency, has a startingtorque of 1.35 times and a maximum torque of 2.2 times, both with respect to its rated-loadtorque. Ignoring the effects of the stator resistance and rotational losses and assumingconstant rotor resistance, determine the slip rated load, and the rotor current at starting (as a percentage of the rotor current at rated load). The slip at maximum torque is 0.343 if that helps.
{Q.1} A three-phase induction motor runs at almost 1198 revolutions per minute (rpm) at no load and 1112 rpm at full load when supplied from a 60-Hz, three-phase source. (a) How many poles does this motor have? (b) What is the slip in percent at full load? (C) What is the corresponding frequency of the rotor currents? (D) What is the corresponding speed of the rotor field with respect to the rotor and with respect to the stator?
A three phase, 50Hz, 6-pole squirrel cage induction motor runs at 960-rpm on full load. The stand still rotor resistance and reactance per phase are 0.01 ohm and 0.05 ohm respectively. Express the maximum torque developed in terms of full load toque. Find the slip at which the maximum torque occurs.
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.
The rotor resistance and reactance per phase of a 4-pole, 50-Hz, 3-phase induction motor are 0.025 ohm and 0.12 ohm respectively. Make simplifying assumptions, state them and : (i) find speed at maximum torque (ii) find value of additional rotor resistance per phase required to give three-fourth of maximum torque at starting. Draw the equivalent circuit of a single-phase induction motor.
(1) Explain why induction motors are preferred for industrial use. (2) Explain the principle of an induction motor (3) Draw the equivalent circuit of an induction motor and state what each element in the circuit represent. (4) Describe how DC, No- Load and Locked Rotor Tests are performed on an induction Motor.
a) Why the slip of induction motor is never zero, b) What happens if the slip of induction motor is one, c)What is the value of the slip for an induction motor at no load and full load.
Explain in detail the Starting of Induction Motors
Select the answer Questions: 1. Synchronous motor for power factor correction operates at a. No load with over-excited fields b. No load with under-excited fields c. Normal load with minimum excitation d. Normal load with zero excitation 2. What happens if field winding of the synchronous motor is short circuited? a. First, starts as induction motor then run as synchronous motor b. Not start c. Motor will burn out d. Run as induction motor e. Other: (specify)
When drawing the steady state electrical model (for an AC induction motor), is the stator armaturre inductance considered? Why/Why not?