2. A 1100 V, 50 Hz, delta-connected induction motor has a star-connected slip-ring rotor with a phasetransformation ratio of 3-8. The rotor resistance and standstill leakage reactance are 0-0122 and 0-250per phase respectively. Neglecting stator impedance and magnetising current, determine (i) thecurrent at start with slip-rings shorted (ii) the rotor power factor at start with slip-rings shortedrotor current at 4% slip with slip-rings shorted (iv) the rotor p.f. at 4% slip with slipthe external resistance per phase required to obtain arotortheshorted (v)(iii)ringsA in the statorsupplystarting current of 100[() 1157 A (it) 0-048.lag (ili) 742-3 A (iv)lines.0.77 (v) 0-7072)3. A 4-pole, 3-phase, 50 Hz induction

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Answered: 2. A 1100 V, 50 Hz, delta-c…

2. A 1100 V, 50 Hz, delta-c transformation ratio of 3-8 per phase respectively. N current at start with slip-ri rotor current at 4% slip w the external resistance per 3. A 4-pole, 3-phase, 50 Hz i ad

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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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.
Design and develop equivalent circuit model of a single phase Induction motor with th consideration of core losses present with the parameter consideration of stator resistance R1 and reactance X1 and two rotor parameters which includes r2,x2 and magnetising reactance xm. (Illustration is required) Draw by hand please
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;
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 3300-V, 50-Hz, 3-phase, 4-pole, star-connected induction motor has identical primary and referred secondary impedances of value 3 + j9 ohm per phase. The turns-ratio per phase is 3/I (stator/rotor), and the rotor winding is connected in delta and brought out to slip rings. Calculate: the full-load torque at rated slip of 5%; the maximum torque at normal voltage and frequency; the supply voltage reduction which can be withstood without the motor stalling; the maximum torque if the supply voltage and frequency both fall to half normal value; the increase in rotor-circuit resistance which, at normal voltage and frequency, will permit maximum torque to be developed at starting. Express this: as a fraction of normal R2and as (3) ohmic values to be placed in series with each of the slip-ring terminals and star connected.
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 three-phase, Y-connected, 220 V, 5 kVA, salient-pole synchronous generator is employed to supply power to a load with unitary fp. By means of a slip test, the direct-axis synchronous reactance is determined to be 12 Ω and the quadrature-axis synchronous reactance, 7 Ω. Consider that the rated current is delivered to the load at the rated voltage and that the armature resistance is negligible. (a) Calculate the corresponding value of the excitation voltage. (b) What is the value of the internal phase shift angle? (c) What is the value of the power angle?
A 4-pole, 50 hz, 3-phase induction motor has a slip-ring rotor with resistance and standstill reactance of 0.04 ohm and 0.2 ohm per phase respectively. Find the amount of resistance to be inserted in each rotor phase to obtain full-load torque at starting. What will be the approximate power factor in the rotor at this instant? The slip at full-load is 3 percent.
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.
A 75kW, 440V, 3-phase, 6-pole,50Hz wound rotor induction motor has a full load slip of0.04 and the slip at maximum torque of 0.2 when operating at rated voltage and frequencywith rotor winding short circuited at the slip rings. Assume the stator resistance androtational losses to be negligible. Find(a) Maximum torque(b) Starting torque(c) Full load copper loss.The rotor resistance is now doubled by adding an external series resistance.Determine(d) Slip at full load(e) full-load torque(f) slip at maximum torque
17. A single-phase, 120 V, 60 Hz, four-pole, split-phase induction motor gave the following blockedrotor test data:VIP Main winding 32 4 80Auxiliary winding 40 4 128a) Determine the standstill impedances of the main and auxiliary windings.b) Determine the values of the resistances to be added in series with the auxiliary winding to obtain maximum starting torque.c) Compare the starting torques and starting currents with and without the added resistance in the auxiliary winding circuit if the motor is connected to a 120 V, 60 Hz supply
A 4-pole, 3-phase, 50Hz induction motor has a voltage between slip-rings on open circuit of 520V. The star connected rotor has a standstill reactance and resistance of 2.0 and 0.4 Ω per phase respectively. Determine: (a) The full-load torque if full load speed is 1,425 rpm(b) The ratio of starting torque to full-load torque(c) The additional rotor resistance required to give maximum torque at standstill.