machinery 5.Obtain an expression for the condition of maximum torque of an induction motor. Sketch the torque-slip curves for several values of rotor circuit resistance and indicate the condition for maximumtorque to be obtained at starting.If the motor has a rotor resistance of 0.02 2 and a standstill reactance of 0.1 2, what must be thevalue of the total resistance of a starter for the rotor circuit for maximum torque to be exerted atstarting ?b..

5. Obtain an expression for the condition of maximum torque of an induction motor. Sketch the torque slip curves for several values of rotor circuit resistance and indicate the condition for maximun torque to be obtained at starting. If the motor has a rotor resistance of 0.02 2 and a standstill reactance of 0.1 2, what must be th value of the total resistance of a starter for the rotor circuit for maximum torque to be exerted a starting ?

5. Obtain an expression for the condition of maximum torque of an induction motor. Sketch the torque slip curves for several values of rotor circuit resistance and indicate the condition for maximun torque to be obtained at starting. If the motor has a rotor resistance of 0.02 2 and a standstill reactance of 0.1 2, what must be th value of the total resistance of a starter for the rotor circuit for maximum torque to be exerted a starting ?

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...

See similar textbooks

Similar questions

What is Equation to find Slip, Output horse power, Torque, Stator current, p.f, Efficiency, From this result and we have Frequency and poles this result from load test of an induction motor
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.
a. A three-phase, 220-V, 60-Hz induction motor runsat 1,140 r/min. Determine the number of poles (forminimum slip), the slip, and the frequency of therotor currents.b. To reduce the starting current, a three-phasesquirrel cage induction motor is started byreducing the line voltage to Vs/2. By what factorare the starting torque and the starting currentreduced?
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?
When drawing the steady state electrical model (for an AC induction motor), is the stator armaturre inductance considered? Why/Why not?
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 at the maximum torque;
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.
A 80 kW, 480-V, 60-Hz, six pole induction motor has a slip of 5 percent when operating at fullload conditions. At full-load conditions, the friction and windage losses are 300 W, and the core losses are 400 W. For full-load conditions, compute the induced torque,T-ind, in N-m.
[1] On an energy point of view, discuss why is it advantageous to run induction motors in star mode when the load less than 50%?
Type your question here Prove that the power developed by a three-phase induction motor is maximum when the equivalent load resistance RL is equal to the magnitude of the standstill impedance of the motor Zol. Then find the maximum power and slip at which occurs.
A three-phase induction motor, at rated voltageand frequency, has a starting torque of 140 percentand a maximum torque of 210 percent of full-loadtorque. Neglect stator resistance and rotational lossesand assume constant rotor resistance. Determinea. The slip at full load.b. The slip at maximum torque.c. The rotor current at starting as a percentage offull-load rotor current.
The air-gap flux density of a two-pole induction motor is given by B=Bm cos(ωt−θ)where Bm is the peak flux density, θ is the angular displacement around the air gap, and we have assumed clockwise rotation. Give the corresponding expression for the flux density of a four-pole induction motor; of a six-pole induction motor.