Calculate motor efficiency, Electrical Engineering

Assignment Help:

1. A self excited shunt generator supplies a load of 12.5 kw at 125 volts. The field resistance is 25 ohms and the armature resistance is 0.2 ohms. The total voltage drop because of brush current and armature reaction at this load is 3 volts. Calculate the induced armature voltage.

2. A 6 pole lap-wound armature having 720 conductors, rotates in a field of 20.35 mWb. (a) If the induced current is 72 A, what is the torque developed by armature? (b) If the induced armature voltage is 410V, what is the motor speed?

3. A shunt motor runs at 1100 rpm at 230v and draws a line current of 40 A. The output power(at the shaft) is 10.8 h.p. The various losses are core loss, 200W: friction and windage loss 140W: electrical loss due to brush contact, 32W: stray load loss, 31W. The armature and field-current resistance are 0.2 ohms and 220 ohms respectively. Calculate (a) motor efficiency, (b) the speed if the output power is reduced by 50%.

4. A 4 pole motor is lap wound with 728 conductors and has a flux of 25 mWb per pole. The armature takes 50 A in current: the resultant demagnetizing effect due to armature reaction reduces the air gap flux by 5%. Calculate the developed torque.

5. One of three fuses protecting a 3-phase electric heater rated at 200kW, 600 V is removed so as to reduce the heat produced by the boiler. What power does the heater develop under these conditions?

 


Related Discussions:- Calculate motor efficiency

Several forms of interference, Q. Several forms of interference? Interf...

Q. Several forms of interference? Interference may take several forms: ac hum, higher frequency pulses and "whistles," or erratic waveforms commonly known as static. Interferin

Transformer, What is the difference between primary and secondary winding o...

What is the difference between primary and secondary winding of transforme

Electronics, what is the difference between half &full wave rectifier

what is the difference between half &full wave rectifier

Zero flag - sub subtract instruction , Zero Flag Since results  is n...

Zero Flag Since results  is non  zero in this  example zero  flag is reset.

How speech is transmitted in digital switching environment, Q. How speech i...

Q. How speech is transmitted in digital switching environment by using PCM/TDM? Ans: A digital carrier system is a communications system which uses digital pulses instead of

Designing 100 line exchange using uni-selector, Q. Designing 100 line excha...

Q. Designing 100 line exchange using Uni-selector? Here three different designing methods for 100 line exchange are discussed: Design: Strowger switching system is designe

What is transient program area, What is TPA (transient program area)? T...

What is TPA (transient program area)? The memory system is divided in three major parts: transient program area, System is and XMS that is extended memory system.

Amplifiers, what is the use of capacitors in amplifiers

what is the use of capacitors in amplifiers

Cro, role of trigger circuit in cro

role of trigger circuit in cro

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd