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

Battery service provider system specification, The vehicle batteries shall ...

The vehicle batteries shall be owned by the battery service provider. The automobile battery shall be recyclable, environmentally friendly, and safe. The battery service pr

Astable multivibrator circuit, how does this circuit work and what are th e...

how does this circuit work and what are th electrical components in it do?

Capacitor filter, Capacitor Filter: A capacitor filter is connect...

Capacitor Filter: A capacitor filter is connected directly across the load is displayed in figure. The property of a capacitor is that it permits ac component and blocks

Find the current flow through a resistor, Q. Find the current flow through ...

Q. Find the current flow through a resistor ? Consider the circuit shown in Figure (a). Reduce the portion of the circuit to the left of terminals a-b to (a) a Thévenin equival

Mode1 - power supplies , Mode1 When the positive  pulse  from PWM  is a...

Mode1 When the positive  pulse  from PWM  is applied to the transistor Q shown  in figure  it gets  turned  on. In  this condition current  flows  through  transistor Q and.

Public safety - application of software defined radio, Public safety - Appl...

Public safety - Application of Software Defined Radio During emergency situation such as earthquake, tsunami, terrorist attack, public safety officials from different agencies

Advantages and disadvantages of alloying steel with silicon, State the adva...

State the advantages and disadvantages of alloying steel with silicon for use as magnetic materials in transformer and electric machines. Extensive utilize, is made of iron-sil

Calculate the voltage regulation, The per-phase synchronous reactance of a ...

The per-phase synchronous reactance of a three-phase, wye-connected, 2.5-MVA, 6.6-kV, 60-Hz turboalternator is 10 . Neglect the armature resistance and saturation. Calculate the v

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