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

Determine the rated stator current, A three-phase, wye-connected, 2300-V, f...

A three-phase, wye-connected, 2300-V, four pole, 1000-kVA, 60-Hz synchronous machine has a synchronous reactanceXs = 5, a field resistance Rf = 10, and an approximately linear ma

Explain procedure to test the power line, Explain procedure to take shut do...

Explain procedure to take shut down and to test the power line before starting work? Ans: Study the circuit and find out the circuit breaker to be opened. Open and lock the c

D.c machine, What are the advantages of distributing windings in an alterna...

What are the advantages of distributing windings in an alternator?

About semi conductor, explain compensation and charge neutrality in GaAs

explain compensation and charge neutrality in GaAs

Explain about concentrator expande, In second technique, a concentrator exp...

In second technique, a concentrator expander (CE) is used near cluster of users and another one at exchange end as demonstrated in figure. Only a few junction lines are run between

Explain working of encoders, Explain working of Encoders? Encoding is t...

Explain working of Encoders? Encoding is the process of forming an encoded representation of a set of inputs, and it is the converse of the decoding operation. An encoder is a

Determine the output voltage increment, (a) Design a 6-bit R-2 R ladder D/A...

(a) Design a 6-bit R-2 R ladder D/A converter. (b) For V ref = 10 V, find the maximum output voltage. (c) Determine the output voltage increment. (d) If the output voltag

Single phase full wave controlled rectifier , Single Phase Full Wave Contro...

Single Phase Full Wave Controlled rectifier The single  phase  half  wave controlled  rectifier  produce only one pulse  of load  current  during  one cycle  of supply voltage

Charging of the capacitor, Charging of the capacitor: Considering the ...

Charging of the capacitor: Considering the below diagram, with slight approximation the ripple voltage can be supposed as triangular. To the cut-out point from the cut-in poin

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