A synchronous, three-phase motor, connected in Y, with a frequency of 60Hz, 2300V, has a synchronous reactance of 110 per phase. The synchronous motor is a smooth pole motor. When delivering 200HP, the efficiency is calculated to be 90%, neglecting losses in the magnetic field. The power factor angle is 15 electrical degrees. Also neglect the ohmic resistance of the windings and calculate: a) The induced excitation voltage per phase. b) The line current. c) The power factor of the synchronous motor.

A synchronous, three-phase motor, connected in Y, with a frequency of 60Hz, 2300V, has a synchronous reactance of 110 per phase. The synchronous motor is a smooth pole motor. When delivering 200HP, the efficiency is calculated to be 90%, neglecting losses in the magnetic field. The power factor angle is 15 electrical degrees. Also neglect the ohmic resistance of the windings and calculate: a) The induced excitation voltage per phase. b) The line current. c) The power factor of the synchronous motor.

Electric Motor Control

10th Edition

ISBN:9781133702818

Author:Herman

Publisher:Herman

Chapter39: Synchronous Motor Operation

Section: Chapter Questions

Problem 14SQ: Induction motors and welding transformers require magnetizing current, which causes a. lagging power...

See similar textbooks

Similar questions

1. The operation of Commutator in DC Motor is * O a) to convert dc to ac O b) to convert ac to dc O c) to convert fixed dc to variable dc O reverse the current direction in the rotating windings each half turn
In general, which of the following is/are a factor that will determine the synchronous speed of a 3-phase motor? 4. a) frequency b) number of stator poles per phase c) both "a" and "b" d) neither "a" nor "b"
8. The synchronous speed of a 3-phase induc- tion motor having 20 poles and connected to a 50 Hz source is ........ (i) 600 r.p.m. (iii) 1200 r.p.m. (ii) 1000 r.p.m. (iv) 300 r.p.m.
The emf induced in the dc generator armature winding is * O AC and DC O DC O None of the above O AC
A three-phase induction motor operates at a slip of 3% and has a rotor copper loss of 300W. The rotational loss is 1500W. Determine (a) the airgap power and (b) the power output.
A four-pole, wave-wound generator has 220 coils of 10 turns each. The resistance of each turn is 0.02 2. Find the resistance of the armature winding.
The rotor of a 3-phase, 60 Hz, 4-pole induction motor takes 118 kW at 3Hz. The motor has stator copped loss of 2.95 kW, a mechanical loss of 2kW and a stator core loss of 1.7 kW. Solve for the motor efficiency
What will be the operating power factor of a 3-phase induction motor, whose ratings are 230 V, 50 Hz, 120 hp, and 4-poles? Motor is operating at rated conditions with an efficiency of 92% and draws a line current of 260 A. The core loss and stator copper losses are 1710 W and 2830 W respectively. (a) 0.85 (c) 0.93 (b) 0.90 (d) 0.80
1. Write down some advantages and disadvantages of different connections of three-phase transformers . (Write mainly for delta-delta, wye-wye, wye-delta and delta-wye)2. What is skew effect? Why is it important for the rotor of an induction motor?
An induction motor is an O stepper motor O asynchronous machine. O DC machine O synchronous machine example of
4. An induction motor draws 4.5 A at a 0.75 lagging power factor from a 208V, 60 Hz source. a) What value of capacitance must be connected in parallel with the motor to raise the overall p.f. to 1. b) Calculate the magnitudes of the motor current, capacitor current and source current with the capacitor in place. 5. A 3-phase Y-connected motor is connected to a three phase Y-conected source with 440V line voltage. It draws a line current of 5A from the source. If the power factor of the motor is 0.8, calculate a) Active power and Reactive power absorbed by the load b) Total Apparent power
If two 3-phase induction machines are mechanically coupled with each other. The two machines are supplied by 50 Hz and 60 Hz, respectively. the speed of the combination of both machines will be: