4- A double squirrel-cage induction motor has (a) Two series winding in stator (c) Two parallel winding in rotor (b) Two parallel windings in stator (d) Two rotors moving in opposite direction 5 The rotor slots are slightly skewed in squirrel cage induction motor to ---------- (a) Increase the strength of rotor bars (b) Reduce the magnetic hum and locking tendency of ro (d) Provide ease of fabrication (c) Economize on the copper to be used 6- Stable operation of an induction motor is (a) Between zero slip and unity slip (b) Between zero slip and slip corresponding to maximum tor (e) Between 6.5 slip and 0.95 slip (d) Between slip corresponding to maximum torque and unity 7- Iron loss in the rotor of a 3-phase induction motor is negligible due to (a) Very low frequency of emf induced in the rotor (b) Very low emf induced in the rotor (c) Very low flux density in rotor parts (d) Constant magnitude of flux linking the rot

4- A double squirrel-cage induction motor has (a) Two series winding in stator (c) Two parallel winding in rotor (b) Two parallel windings in stator (d) Two rotors moving in opposite direction 5 The rotor slots are slightly skewed in squirrel cage induction motor to ---------- (a) Increase the strength of rotor bars (b) Reduce the magnetic hum and locking tendency of ro (d) Provide ease of fabrication (c) Economize on the copper to be used 6- Stable operation of an induction motor is (a) Between zero slip and unity slip (b) Between zero slip and slip corresponding to maximum tor (e) Between 6.5 slip and 0.95 slip (d) Between slip corresponding to maximum torque and unity 7- Iron loss in the rotor of a 3-phase induction motor is negligible due to (a) Very low frequency of emf induced in the rotor (b) Very low emf induced in the rotor (c) Very low flux density in rotor parts (d) Constant magnitude of flux linking the rot

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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:Adding inductance to the rotor circuit will .Decrease starting current and starting torque O .Increase starting current and starting torqueO .Decrease starting current and increase starting torque O
A 3-phase, 400/200 V, Y-Y connected wound-rotor induction motor has 0.06 Q rotor resistance and 0.3 Q standstill reactance per phase. To make the starting torque equal to the maximum torque, the additional resistance required in the rotor circuit will be O 0.24 0/phase O 0.42 0/phase O 0.34 Q/phase O 0.52 Q/phase
A 460-V, 25-hp, 60-Hz, four pole, Y-connected induction motor has the following impedances in ohms per phase referred to the stator circuit: R₁ = 0.641Ω R₂ = 0.3320 X₁ = 1.106Ω X₂ = 0.464Ω RM = 26.3Ω The total rotational losses are 1100 W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 2.2 % at the rated voltage and rated frequency, find the motor's a) Speed d) Pconv and Pout b) Stator current e) Tind and Tload c) Power factor f) Efficiency Activate
A 460-V, 25-hp, 60-Hz, four pole, Y-connected induction motor has the following impedances in ohms per phase referred to the stator circuit: R₁ = 0.641Ω R₂ = 0.3320 X₁ = 1.106Ω X₂ = 0.464Ω RM = 26.3Ω The total rotational losses are 1100 W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 2.2 % at the rated voltage and rated frequency, find the motor's a) Speed d) Pconv and Pout b) Stator current e) Tind and Tload c) Power factor f) Efficiency Activate
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The starting torque of slip ring induction motor is High Negligible Medium O Low
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