The full-load slip of a 4-pole, 60 Hz, 440 V (line-to-line) three-phase induction motor is 0.05. What is the speed of the rotating stator field? What is the frequency (in Hz) of the rotor current? i. When the output power of the motor is 90 hp at a speed of 1732 rpm, rotational losses (which include frictional and core losses) are 10,100 W, while copper losses for both the rotor and stator total 3700 W. Determine the motor efficiency and line current, assuming the motor has a 0.8 pf lagging under these conditions. ii.

The full-load slip of a 4-pole, 60 Hz, 440 V (line-to-line) three-phase induction motor is 0.05. What is the speed of the rotating stator field? What is the frequency (in Hz) of the rotor current? i. When the output power of the motor is 90 hp at a speed of 1732 rpm, rotational losses (which include frictional and core losses) are 10,100 W, while copper losses for both the rotor and stator total 3700 W. Determine the motor efficiency and line current, assuming the motor has a 0.8 pf lagging under these conditions. ii.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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d) A 2-pole induction motor is fed with a 230 V, 50 Hz supply and is running at no load. i. Calculate its angular speed in rpm. ii. Explain how can we slow down the speed of the motor above, at no load? iii. Explain what will happen to the speed of the motor if we slowly add amechanical load to the motor.
Q2. A 230 V single-phase induction motor, 50 Hz, has the following winding impedances (at rest): Zm=28 <70° Q. Za=42 <45°Q A) Calculate the input current at start-up. B) Obtain the amount of capacitor in series with the auxiliary winding for which the torque Maximum startup. Then compare the input current, auxiliary winding current and torque all at start-up in two modes with and without starter capacitor.
what are the disadvantages of slip ring induction motor?
A three-phase, 460 V, 98hp 1,60 Hz, four-pole induction machine delivers rated output power at a slip of 0.05. Determine: (i) The synchonous speed. (V) speed at half Load (ii) The motor speed. (iii) The rotor frequency. (iv) The slip speed. ...A... -
12. The IR-compensation in frequency control of induction motors is used for: a) compensation of the voltage drop in the active resistance of the stator winding. b) compensation of the voltage drop in the inductive reactance of the stator winding. c) keeping the motor voltage constant. d) keeping the motor speed constant U₁ U₁ Us0 0 f. f₁
22. A) Why is the power factor of a lightly loaded 3-phase squirrel-cage induction motor very low? a) most of the power supplied to the motor at light loads is magnetization or inductive power b) most of the power supplied to the motor at light loads is resistive power c) most of the power supplied to the motor at light loads is capacitive power d) none of the above B) What happens to the power factor as load is increased on the motor? a) the power factor increases b) the power factor deceases c) remains the same
A 400 V, 50 Hz 30 hp, three-phase induction motor is drawing 50 A current at 0.8 power factor lagging. The stator and rotor copper losses are 1.5 kW and 900 W respectively. The friction and windage losses are 1050 W and the core losses are 1200 W. The air-gap power of the motor will be
7. The total rotational losses of an induction motor are a combination of ------- A) Friction losses B) Windage losses. D) Stray losses. C) Core losses. 8. The developed mechanical power can be calculated using the equation of- A) PAG - PRCL. B) PAG w sync C) (1-s) PAG. D) 3 E2Gc. 9. For an induction motor, if the synchronous speed is 1800 r/m, and the rotor speed 180rad/sec, then the slip will be: A) 5.5% C) 6% B) 4.5% D) 4% 10. The power losses in the stator part of the induction motor are B) Core losses D) Friction and windage losses A) Stator copper losses C) Air-gap losses
A three-phase, 460 V, 98hp 1,60 Hz, four-pole induction machine delivers rated output power at a slip of 0.05. Determine: (i) The synchonous speed. (V) speed at half Load (ii) The motor speed. (iii) The rotor frequency. (iv) The slip speed. ...A... -
3. A 440V 60-hp six pole 60 hz A connected induction motor has the following parameters R1=0.048 R2= 0.035 Xm= 9.50 X1= 0.33 0 X2= 0.37 0 Pcore= 600W PF&W= 350W Use the Thevenin's Equivalent circuit concept to find: (a)Vth and Zth seen by the rotor circuit (b)The slip at which maximum torque occurs (c) the value of Max/pullout Torques (d) The starting torque.