2. A 3-phase, 400-V, Y-connected induction motor has an equivalent T-circuit consisting of R = 1 2, X, = 2 SN, equivalent rotor values are R,' = 1.22, X,' = 1.5 Q. The exciting branch has an impedance of (4 +j 40) 2. If slip is 5% find (i) current (ii) efficiency (iii) power factor (iv) output. [ (i) 10.8 A (üi) 81% (iii) 0.82 (iv) 5 kW] Assume friction loss to be 250 W.

2. A 3-phase, 400-V, Y-connected induction motor has an equivalent T-circuit consisting of R = 1 2, X, = 2 SN, equivalent rotor values are R,' = 1.22, X,' = 1.5 Q. The exciting branch has an impedance of (4 +j 40) 2. If slip is 5% find (i) current (ii) efficiency (iii) power factor (iv) output. [ (i) 10.8 A (üi) 81% (iii) 0.82 (iv) 5 kW] Assume friction loss to be 250 W.

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

The stator resistance of a 1-phase induction motor is 2.5 ohms and its leakage reactance is 2.0 ohms. 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.
A 480V, 60Hz, six-pole, Y connected cage rotor induction motor has the followingparameters in ohms per phase referred to the stator: R1=0.5ΩX1=1.1Ω R2=0.45ΩX2=0.6Ω Xm=30Ω The total rotational losses (friction, windage, and core losses) are 1100W and are assumedto be constant. For a rotor slip of 2.2% at the rated voltage and rated frequency, calculate:d) The air-gap power (Pag) and the developed mechanical power (Pconv)e) Developed electromechanical torque, and the output mechanical torquef) Efficiency
A 208 V, 60 Hz, 2-pole, Y-connected induction motor is rated at 16 hp. Its equivalentcircuit components have the following values:(R1 = 0.200 ohm, X1 =0.410 ohm); (R2 = 0.120 ohm, X2 = 0.410 ohm); Xm = 15.0 ohm.Rotor slip is 4.5% at the rated voltage and frequency. Mechanical and core losses are 230Wand 200W respectively. Find (a) rotor speed (b) line current and motor p.f (c) Air-gap andconverted power (d) Induced torque.
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.
QI: The parameters of a 4 kW, 220V. 2-phase induction motor, in ohms per phase, are: r1=0.53, x1 =2.4, XM= 70, r2 = 0.96, x2 = 3.0. The motor is operated from unbalanced 2- phase source whose voltages are 230V and 210V, the smaller voltage is lagging the larger by 800. For a slip of 5% and rotational losses of 30 W, find the positive- and negative- sequence components of: (a) the applied voltages. (b) Find the values of phase currents (c) the input current. (d) Find the developed mechanical power. (e) Find the efficiency.
A 3-phase, 6 pole, 440 V, 60 Hz, Y-connected induction motor has the following impedances per phase referred to the stator circuit: R1=0.43 Ω, R2=0.54 Ω, X1=1.263 Ω, X2=0.608 Ω, XM=43Ω 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 percent at the rated voltage and rated frequency, Find the motor speed, stator current, output power
3) The conversion ratio of an asynchronous motor with 415 V, 3-phase, 60Hz, 6-pole, Y-connected rotor winding is a = N1 / N2 = 1.5,Parameter values per phase transferred to the stator are given below. a) For the case where slip s = 0.05, calculate the stator current, the torque generated in the motor, with the rotor circuit voltageCalculate the frequency.b) Subtract the Thevenin equivalent.c) The rotor stays stuck while the motor is running under load. Find the rotor current reflected to the stator at this instant.d) Find the maximum torque the motor can produce.e) It is required that the engine initially develops with maximum torque. For this, externalFind the value of the resistance transferred to the stator
A 200V, 3, star connected induction motor takes 30A at a line voltage of 35V with rotor locked. With this line voltage, power input to motor is 450W and core loss is 60W.The dc resistance between a pair of stator terminals is 0.15Ω. If the ratio of ac to dc resistance is 1.6, find the equivalent leakage reactance/phase of the motor and the stator and rotor resistance per phase.
A 460V, 25hp, 60Hz, 4 pole, Y-connected induction motor has the following impedances in ohms per phase referred to the stator circuit: R1 = 0.641 Ω R2 = 0.332 Ω X1 = 1.106 Ω X2 = 0.436 Ω Xm = 26.3 Ω The total rotational losses are 1100W and are assumed to be constant. The core loss is lumped in with the rotational losses. For a rotor slip of 3.5% at the rated voltage and rated frequency, find the motor’s Speed Stator current Power factor Pconv and Pout Ʈǐnd and Ʈload Efficiency
A 480V, 60Hz, six-pole, Y connected cage rotor induction motor has the followingparameters in ohms per phase referred to the stator: R1=0.5Ω X1=1.1Ω R2=0.45ΩX2=0.6Ω Xm=30Ω The total rotational losses (friction, windage, and core losses) are 1100W and are assumedto be constant. For a rotor slip of 2.2% at the rated voltage and rated frequency, calculate:a) Rotor speedb) Stator currentc) Complex, real, and reactive input power and the power factor of the machined) The air-gap power (Pag) and the developed mechanical power (Pconv)e) Developed electromechanical torque, and the output mechanical torquef) Efficiency
A three-phase Y-connected 230-V (line-to-line) 7.5-kW 60-Hz six-pole induction motor has the following parameter values in Ω/phase referred to the stator: R1 = 0.294, R2 = 0.144 X1 = 0.503, X2 = 0.209, Xm = 13.25 The total friction, windage, and core losses may be assumed to be constant at 403 W, independent of load. For a slip of 4 percent, determine: (a) stator current, power factor, (b) output torque and power,(c) efficiency when the motor is operated at rated voltage and frequency, (d) the load component 12 of the stator current, the induced torque Tind, and the converted power Pconv for a slip s= 0.04,(e) the maximum torque and the corresponding speed; and (f) the starting torque Tst and the corresponding stator load current 12 start
A certain six-pole 440-V-rms 60-Hz three-phase delta-connected induction motor has Rs=0.08 ΩRr′=0.06 Ω Xs=0.20 ΩXr′=0.15 Ω Xm=7.5 Ω Neglecting the rotational losses, find the no-load speed, line current, and power factor for the motor.