Electromagnetic torque , Electrical Engineering

Assignment Help:

Electromagnetic torque 

The torque is given by the force on the armature winding multiplied by its radius. Force on a conductor in magnetic field B is: 

F=B.I.L

so, T=B.I.L.R

The torque opposes the mechanical rotation of the rotor and so the mechanical torque turning the generator must do work against the electromagnetic torque in order to generate the voltage (and current) supplied to the electrical load connected to the generator. Therefore energy conversion occurs from mechanical energy to electrical energy.The flux density B webers/m  can be expressed in terms of the flux per pole, φ,  to give a relation between the electromagnetic torque to be overcome and current produced.

T=Cm.Ø.Ia

C=machine constant

The equivalent circuit representation of an electrical generator is:

 

 

478_Electromagnetic torque.png

 

The generator itself provides the source tosupply the field current I . Residualmagnetism will provide a small generatedcurrent at first that then builds up as thefield current grows, producing moregenerated current, etc. [NB leaving analternator open circuit will cause thevoltage to build up to the point wherediodes used to rectify the output voltagecan be damaged. Never operate an alternator without an electrical load connected. The output voltage is slightly less than the generated voltage due to the volt drop across the armature winding resistance when current flows. The arrangement of connecting the field winding in parallel with the armature is known as a shunt connected machine. The alternative is to connect the field winding in series with the armature, in which case it as known as a series connected machine.

Reversibility principle of electric machines

An electric machine can be operated as a generator or motor depending on the operation conditions. This is known as the reversibility principle of electric machines. For example, if the generator above is supplied from an electrical source, it will operate as a motor

 

 


Related Discussions:- Electromagnetic torque

Explain the asynchronous up-down counters, Explain the Asynchronous Up-Down...

Explain the Asynchronous Up-Down Counters? In some applications a counter must be able to count both down and up and the circuit below is a 3-bit up-down counter. It counts do

Speed control of ac machine, what is meant by pole changing methods in ind...

what is meant by pole changing methods in induction motor

wind turbine, pls how can i stat up building wind turbin

pls how can i stat up building wind turbine

Frequency-controlled induction-motor drives, Q. Frequency-controlled induct...

Q. Frequency-controlled induction-motor drives ? The converters employed for variable-frequency drives can be classified as: • Voltage-source inverter (which is the only one

What digits are represented by the signal, A signal stands for 0110 with po...

A signal stands for 0110 with positive logic in which low stands for 0 and high stands for 1. If negative logic (in which low stands for 1 and high stands for 0) is used, what digi

How does voice one dsl work?, Question 1 Define the term telecommunication...

Question 1 Define the term telecommunication? Discuss briefly the various uses of telecommunication in daily life Question 2 Explain the powers and functions of the TRAI

Tvm, Why is the signal first attenuated and then amplified?

Why is the signal first attenuated and then amplified?

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