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

Calculating the damping ratio of the system, Consider the following mechani...

Consider the following mechanical system: a) Write a differential equation that describes the motion for this system. b) Take the Laplace transform of this equation and

What is polyphase induction machine performance, Q. What is Polyphase Induc...

Q. What is Polyphase Induction Machine Performance? Some of the important steady-state performance characteristics of a polyphase induction motor include the variation of curre

Ramp type dvm, use of ranging and attenuator circuit

use of ranging and attenuator circuit

Illumination, Ask question #Minimum 100A light assembly shop, 15 m long, 9 ...

Ask question #Minimum 100A light assembly shop, 15 m long, 9 m wide and 3 m up to trusses is to illuminated to a level of 200 lux. The utilization and maintenance factors are resp

Image retreval and face recognization technique, block diagram of eigen fac...

block diagram of eigen face,Viola & Jones Method,Bio-ID,RWTH-i6 Groups of People Database

Carthode ray oscilloscope, with a simple circuit,explain the construction o...

with a simple circuit,explain the construction of Direct Reading Probe of a cathode ray oscilloscope

Explain microprocessor development system, Explain Microprocessor developme...

Explain Microprocessor development system. Microprocessor development system: Computer systems consist of undergone many changes lately. Machines which once filled large area

truth table in sop form, Normal 0 false false false EN...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What is the function of mode set register in 8257, What is the function of ...

What is the function of mode set register in 8257? The mode set register is used for programming the 8257 as per the needs of the system. The function of the mode set register

Dc generator, A 20kw 220v shunt generator has armature resistance of 0.07 a...

A 20kw 220v shunt generator has armature resistance of 0.07 and a shunt field resisitance 900 ohm find field loss?

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