1. The rated current of 15 hp, 220V sepurately excited DC motor is- a) 50.87A 2 If the load torque T of induction motor proportional to square of the rated speed, what will he the value of load torque if the motor speed teduces to half rated speed. b) 60.2 A c) 4031A a) 2-T b) 4 T e) 4«TL 3. In stator voltage control strategy of induction motor, the variable stator voltage will be: a) abuve rated voltage h) below thuan rated voltage e) above and below rated voltage 4. The constant torque operation of separately escited de motor can be obtained: a) constant field current. b) costunt armature curtent. clconstant field and armature current 5. The speed control of AC motor using current control is done hy using a) Voltage Source inverter b) Current source inverter e) AC voltage controller.

1. The rated current of 15 hp, 220V sepurately excited DC motor is- a) 50.87A 2 If the load torque T of induction motor proportional to square of the rated speed, what will he the value of load torque if the motor speed teduces to half rated speed. b) 60.2 A c) 4031A a) 2-T b) 4 T e) 4«TL 3. In stator voltage control strategy of induction motor, the variable stator voltage will be: a) abuve rated voltage h) below thuan rated voltage e) above and below rated voltage 4. The constant torque operation of separately escited de motor can be obtained: a) constant field current. b) costunt armature curtent. clconstant field and armature current 5. The speed control of AC motor using current control is done hy using a) Voltage Source inverter b) Current source inverter e) AC voltage controller.

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...

See similar textbooks

Similar questions

Explain the conditions for parallel operation of synchronous generators. A three phase, wye connected, synchronous generator is rated 150 MW, 0.85 lagging power factor, 12.6 kV, 60 Hz, and 1800 rpm. Each winding has an armature resistance of 0.05Q and a synchronous reactance of 0.6Q. Draw the phasor diagram with values, show torque angle and determine the induced voltage for the condition of rated load.
Q2: Correct the wrong statement if any: 1-The series filed of a series de generator is excited by armature current. 2- The developed power in DC generator armature is function to load current. 3-The commercial efficiency of DC generators is relationship between output mechanical power and developed power in armature winding. 4- If the source frequeney subjected to primary windings increased, the iron losses also decreased. 5-In transformers short circuit test primary voltage will be greater than secondary voltage. GOOD LUCK
4) A 40-kW induction motor, with a lagging power factor of 0.76 is supplied by a 120-Vrms, 60-Hz sinusoidal voltage source. Find the capacitance needed in parallel with the motor to raise the power factor to 0.9 lagging
1a
15. The main and auxiliary windings of a hypothetical 130-V, 60-Hz, split-phase motor have the following locked-rotor parameters: Rmw = 2.3 Ohms, Xmw = 3.0 Ohms, Raw = 9.25 Ohms, and Xaw = 8.2 Ohms. The motor is connected to a 130-V, 50-Hz system. Determine the capacitance, in microfarad, required in series with the auxiliary winding in order to obtain a 86 degrees phase displacement between the currents in the two windings. Correct Answer: 222.33
The stator resistance of a 1-phase induction motor is 2.5 ohm and its leakage reactance is 2.0 ohm. Onno-load, the motor takes 4 A at 96 V and at 0.25 lagging power factor. The no-load friction andwindage loss is negligible. Under the blocked-rotor condition, the input power is 130 W at 6 A and42 V. obtain the equivalent circuit parameters.
If the average pole flux of a dc machine with 24 coils, each of which contains 16 windings, 4 poles, double layered parallel winding (duplex lap winding), with a speed of 1000 rpm, is 15mWb, what is the idle winding voltage and (Note: In your operations, two digits after the comma) take it)
Exercise 2 A shunt generator delivers 14A at 270V and the resistance of the shunt field and armature are 100 Q and 0.75 Q2, respectively. Calculate: i. The generated emf and the efficiency of this operating condition. ii. The generated emf if the shunt field impedance was triple and if it was double and the efficiency of these cases. iii. What emf could serve tha same active power of load but at load voltage of 240V and the efficiency in this case.
Question A 3-phase, 415 V, 4-pole, 50 Hz induction motor draws 5 times the rated current at rated voltage at starting. It is required to bring down the starting current from the supply to 2 times of the rated current using a 3-phase autotransformer. If the magnetizing impedance of the induction motor and no-load current of the autotransformer is neglected, then the transformation ratio of the autotransformer is given by
h has rotor e.m.f. Speed of the induction motor and the frequency of its [970 r.p.m.; 1.5 Hz] 4. A 3-phase, 50-Hz induction motor with its rotor star-connected gives 500 V (r.m.s.) at standstill between the slip-rings on open-circuit. Calculate the current and power factor at standstill when the rotor winding is joined to a star-connected external circuit, each phase of which has a resistance of 10 2 and an inductance of 0.04 H. The resistance per phase of the rotor winding is 0.2 2 and its inductance is 0.04 H. Also, calculate the current and power factor when the slip-rings are short-circuited and the motor is running with a slip of 5 per cent. Assume the flux to remain constant. [10.67 A; 0.376; 21.95 A; 0.303] 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 maximum torque to be obtained at starting. If the motor has a rotor resistance of…
Determine the missing digit 971-05?1-52-8
9