(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 Assuming the rotor and stator copper losses are equal, determine the percentage exceeding the full-load value. What would be the power factor and slip at full-load reduction in voltage which would just permit stable operation at a torque not are in the ratio of 10/1 and the power factor in each case is 0-25. torque with the voltage thus reduced? (14) A 400-hn 1100

(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 Assuming the rotor and stator copper losses are equal, determine the percentage exceeding the full-load value. What would be the power factor and slip at full-load reduction in voltage which would just permit stable operation at a torque not are in the ratio of 10/1 and the power factor in each case is 0-25. torque with the voltage thus reduced? (14) A 400-hn 1100

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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Similar questions

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.
We have a six-pole, 440-V-rms, 60-Hz delta-connected synchronous motor operating with a constant developed power of 20 hp, unity power factor, and a torque angle of 10°. Then, the field current is reduced such that Br is reduced in magnitude by 25 percent. Find the new torque angle and power factor. Is the new power factor leading or lagging?
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.
An eight-pole 240-V-rms 60-Hz delta-connected synchronous motor operates with a constant developed power of 50 hp, unity power factor, and a torque angle of 15°. Then, the field current is increased such that Br increases in magnitude by 20 percent. Find the new torque angle and power factor. Is the new power factor leading or lagging?
A 50-kW, 440-V, 50-Hz, six-pole induction motor has a slip of 6 percent when operating at full-load conditions. At full-load conditions, the friction and windage losses are 300 W, and the core losses are 600 W. Find the following values for full-load conditions: (a) The shaft speed nm (b) The output power in watts (c) The load torque load in newton-meters (d) The induced torque ind in newton-meters (e) The rotor frequency in hertz
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.
Q/ A 3-phase squirrel-cage induction motor, at rated voltage and frequency, has a maximum torque of 225 percent and starting torque of 150 percent of full-load torque. Neglect stator resistance and rotational losses and assume costant rotor resistance. Calculate:i) the slip at maximum torque.ii) the slip at full load.
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?
)A 50-kW, 440-V, 50-Hz, six-pole induction motor has a slip of 6 percent when operating at full-load conditions. At full-load conditions, the friction and windage losses are 300 W, and the core losses are 600 W. Find the following values for full load conditions: (a) The shaft speed nm (b) The output power in watts (c) The load torque τload in newton-meters (d) The induced torque τind in newton-meters (e) The rotor frequency in hertz
The resistance of the armature of a 220-V shunt motor is 0.4 Ω and itsfull-load speed is 1050 r.p.m. Calculate the resistance to be inserted inseries with the armature to reduce the speed with full-load torque to 800r.p.m., the full-load armature current being 5A. If the load torque is thenhalved, at what speed will the motor run ? Neglect armature reaction
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.