4. The total frictional and windage loss of a 3-phase induction motor is 300 W. With a 2% slip, find the %efficiency of the motor when it draws 25 A current at 0.8 p.f. lagging from a 460-V supply and the equivalent rotor resistance referred to stator Rgap = 8.0 ohm
Solution:
4. The total frictional and windage loss of a 3-phase induction motor is 300 W. With...
A 4 phase, 460 V, 60 Hz, 26.8 hp, 4 pole, Y-connected induction motor draws 25 A at a power factor of 0.9 lagging. Core loss is 900 W, stator copper loss is 1100W, friction and winding losses are 300 W, and stray loss is neglected. The machine shaft rotates at 1738 rpm. Calculate the air gap power and output load torque - [Induction Motor - 15 points) A three-phase, 460 V, 60 Hz, 26.8 hp, 4-pole, Y-connected induction motor...
4.6. A 460-V, 75 kW, 4-pole, delta-connected, 60-Hz, three- phase induction motor has a full-load slip of 5 percent, an efficiency of 92 percent and a power-factor of 0.87 lagging at full-load. At start-up, the motor develops 1.9 times the full load developed torque but draws 7.5 times the rated current at the rated voltage. This motor is to be started with an auto- transformer reduced-voltage starter. Assume the stator resistance and the stator core loss to be negligible. Calculate...
The input power to a 480V, 3 phase, 6 pole, 50 Hz induction motor is 75kW with a line current of 75A and runs at a slip of 2.5%. If the stator core loss is 2 kW, windage and friction loss is 1.2 kW, and the stator resistance per phase is 0.16 ohm. Calculate: a. Power supplied to the rotor (Air gap power) b. Rotor copper loss c. Shaft power d. Efficiency of the motor e. Shaft torque f What...
6. [Induction Motor - 15 points] A three-phase, 460 V, 60 Hz, 26.8 hp, 4-pole, Y-connected induction motor draws 25 A at a power factor of 0.9 lagging. The core loss is 900 W, stator copper loss is 1100 W, friction and windage loss is 300 W, and stray loss is neglected. The machine shaft rotates at a speed of 1738 rpm. Calculate the air gap power and output load torque.
Two tests were performed on a 230-V, 60-Hz, 4-pole, Y-connected, three-phase induction motor and the obtained data are given in the table below. The friction and windage loss is 15 W, and the stator winding resistance between any two lines is 3.96ohm Determine: 1) The equivalent circuit parameters of the motor 3) The motor efficiency at a slip of 8%. No-load test 137 0.43 230 Blocked-rotor test 70 1.18 47 3-phase power input, W Line-line voltage, V
6. A 3-phase 2.2 kV 25 Hz squirrel cage induction motor draws a line current of 224 A and a total power of 777 kW when operating at full load. The full-load speed is 245 rpm. The stator is wye connected and has an effective resistance per phase of 0.125 Ω. The stator iron (core) loss is 8.88 kW; friction and windage losses are 4.54 kW. Calculate at full-load conditions: b. power supplied to the rotor, a. the power factor;...
4. A 3-phase, 340 V, Induction motor is supplied with 60 A at .85 pf lagging. Its stator and rotor copper losses are 4000 W and 800 W respectively, while its core losses are 2000 W, and its Friction, Windage and Stray losses are a combined 750 W. Determine: a. Draw a diagram depicting the energy flow in the motor (Similar to the one we had drawn in class) b The air gap power c. The mechanical power developed d....
Problem Solving: 1. A 220V, 4-pole, 60Hz, 1-phase induction motor has an effective rotor resistance and leakage reactance of 0.5 Ohms and 5 ohms respectively. It is running at a speed of 1,800 rpm. Determine: a. Frequencies of forward and backward rotor current components b. Relative magnitudes of forward and backward fluxes. Neglect magnetizing current and stator impedance. A 220-W, 2-pole, 115-V, 60-Hz single-phase induction motor delivers rated output at a slip 10%. The total copper loss at full load...
A 460-V, three-phase, 4-pole induction motor is known to have the following single-phase equivalent-circuit parameters in ohms-per-phase Y R 19.7 x 10-3 Xi=0.129 X2 0.187 Xm 13.9 The motor is observed to be operating at a terminal voltage of 450 V, line-line with an output power of 95 kW at a speed of 1780.7 r/min. Calculate the single-phase equivalent-circuit rotor resistance R2 assuming that the motor core loss is 1200 W and the friction and windage loss is 700 W....
Problem # 3: Induction Motor Analysis [30 points] The parameters of the per phase equivalent circuit of a three phase wye-connected, 220 V (line- line, rms) 10 hp, 60 Hz, six-pole induction motor are given as: Ri = 0.3 Ohm, R2-0.15 Ohm, Xi-0.5 Ohms, X2= 0.2 Ohm, Xm-15.0 The total friction, windage and core losses add up to be a constant of 400 W. For a slip of 0.025 with motor operating at rated frequency and stator voltage, calculate the...