For a power system having induction motor loads, an overexcited synchronous motor is also attached. The the over all power factor O a. Improves b. Remains same O c. becomes upf d. Degrades A load 100+j0 ohms is connected across a 200 V and 50 Hz supply. Find the total current. O a. 1 A O b. 2 A O c. 3 A O d. 3.5 A

For a power system having induction motor loads, an overexcited synchronous motor is also attached. The the over all power factor O a. Improves b. Remains same O c. becomes upf d. Degrades A load 100+j0 ohms is connected across a 200 V and 50 Hz supply. Find the total current. O a. 1 A O b. 2 A O c. 3 A O d. 3.5 A

Electric Motor Control

10th Edition

ISBN:9781133702818

Author:Herman

Publisher:Herman

Chapter33: Four-speed, Two-winding (consequent Pole) Motor Controllers

Section: Chapter Questions

Problem 7SQ: Why are different motor connections shown for what appears to be the same motor in the various...

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Why are different motor connections shown for what appears to be the same motor in the various diagrams in Figure 332? FIG. 332 Typical arrangements for four-speed, three-phase, two-winding motors.
PLEASE ONLY ANSWER THE D E F G PARTS PLEASE ANWSER AS SOON AS POSSIBLE. Thanks in advance. The no-load and locked-rotor test results of a three-phase 10 HP, 220 V, 60 Hz, 6 poles star connected induction motor are;The no-load test:VNL=220 V, PNL=340 W, INL=6.2 AThe locked-rotor test:VSC=54 V, PSC =430 W, ISC =15.2 AThe voltage across the stator windings is 2 V when nominal DC current flows through it. Coefficient for DC resistance is 1,25.a) Calculate the equivalent circuit parameters and draw the complete single-phase equivalent circuit of the induction motor.b) Calculate efficiency of the motor for s=0.06 by using the approximate equivalent circuit (RFe core resistance is not ignored).c) Shaft torque for s=0,06 d) Slip value at the maximum (breakdown) torque,e) Maximum (breakdown) torque of the induction motor.f) Speed of the motor at maximum torque point.g) Rotor frequency at maximum torque.
Q) A 3 phase ,delta connected 410v,50HZ,6 pole Induction motor has the following per phase parameters in ohms refered to the stator. R1 = 0.14Ώ,X1 = 0.44 Ώ ,R2 * = 0.12 Ώ,X2* = 0.43 Ώ,Xm = 28 Ώ.Calculate the stator current and power factor when the motor is operated at rated voltage and frequency with slip 0.03.?
4. A three-phase, 7.5Hp, 230V, 60Hz, Delta connected induction motor was tested and give the following input data:No load Test: I = 10A P = 650W slip = 0.8333%Load Test: I = 19A, P = 6800W slip = 3%Resistance test between two stator terminals: Vdc = 9V , Idc = 20A Assume K = 1.5Determine the efficiency of the motor during the load test
23. As load is increased from no load to full load on a 3-phase squirrel-cage induction motor, what happens to the ...D) stator current of the motor?a) increases b) decreases c) remains the same d) none of the aboveE) power factor of the motor?a)improves, b)get poorer, c)remains the same, d)none of aboveF) efficiency of the motor?a)increases b)decreases c) remains the same d) none
A single-phase, 120 V, 60 Hz, 1/2 hp, 1740 rpm split-phase fan motor gave the following testresults:V I PNo load test 120 4 110Standstill test (main winding) 41 5.8 115Standstill test (auxiliary winding) 38 7 200Main winding resistance = 1.85 Ω.a) Obtain an equivalent circuit for the motor for running conditions.b) Determine the no-load rotational loss.c) Determine the efficiency at the rated speed.
A three-phase, 7.5Hp, 230V, 60Hz, Delta connected induction motor was tested and give the following input data: No load Test: I = 10A P = 650W slip = 0.8333% Load Test: I = 19A, P = 6800W slip = 3% Resistance test between two stator terminals: Vdc = 9V , Idc = 20A Assume K = 1.5 Determine the efficiency of the motor during the load test
Reduced parameters of 480V, 60 Hz, 6 pole, 3 phase, delta connected induction motor to stator are Rs= 0.461 ohm, Rr'=0.258 ohm, Xs=0.507 ohm, Xr'= 0.309 ohm, Rc=100 ohm and Xm=30.74 ohm. given. The motor rotates at 1170 rpm. According to the given values; a) Find the synchronous speed (Ns) in rpm. b) Find the slip (s). c) Find the stator phase current (Is). d) Find the input power (Pin). e) Find the output power (Pout).
Reconnecting Induction Motors 16.a. A 12-pole 575-volt 60-Hz motor has a chord factor o{ 0.892. If the motor is reconnected as a 16-polemotor with a chord factor of 0.968, the operating voltage due to changes in the chord factor and in thespeed isA. 682 voltsB. 780 voltsC. 468 voltsD. 398 volts16.b. If a 10-pole 50-Hz motor should operate at the same speed on a 60-Hz circuit, the motor should bereconnected to produceA. 14 poles.B. 12 poles.C. 16 poles.D. 8 poles.
The no-load and locked-rotor test results of a three-phase 10 HP, 220 V, 60 Hz, 6 poles star connected induction motor are; The no-load test: VNL=220 V, PNL=340 W, INL=6.2 A The locked-rotor test: VSC=54 V, PSC =430 W, ISC =15.2 A The voltage across the stator windings is 2 V when nominal DC current flows through it. Coefficient for DC resistance is 1,25. a) Calculate the equivalent circuit parameters and draw the complete single-phase equivalent circuit of the induction motor. b) Calculate efficiency of the motor for s=0.06 by using the approximate equivalent circuit (RFe core resistance is not ignored). c) Shaft torque for s=0,06 d) Slip value at the maximum (breakdown) torque, e) Maximum (breakdown) torque of the induction motor. f) Speed of the motor at maximum torque point. g) Rotor frequency at maximum torque.
A large 3-phase, 4000 V, 60 Hz, squirrel-cage induction motor draws a current of 385 A and a total active power of 2344 kW when operating at full-load. The corresponding speed is accurately measured and is found to be 709.2 RPM. The stator is connected in wye and the resistance between two stator terminals is 0.10 Ω. The total iron losses are 23.4 kW and the windage and friction losses are 12 kW. Calculate the following: a) The power factor at full load.b) The active power supplied to the rotor.c) The total I²R losses in the rotor.d) The load mechanical power (kW), torque (kN-m) and efficiency (%).
Calculate and plot the torque-speed characteristics for a four-pole induction motor. Themotor parameters are rs = 24.5 Ω, rr =23 Ω, Xs = 10 Ω, Xr = 40 Ω, and Xm = 25 Ω. Therated voltage is 110 V. The maximum frequency of the supplied phase voltages is fmax =60 Hz. Assume the phase voltages are supplied with frequencies 20, 40 and 60 Hz. ...