Electromagnetic torque , Electrical Engineering

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

 

 

Posted Date: 8/23/2012 12:40:40 AM | Location : United States







Related Discussions:- Electromagnetic torque , Assignment Help, Ask Question on Electromagnetic torque , Get Answer, Expert's Help, Electromagnetic torque Discussions

Write discussion on Electromagnetic torque
Your posts are moderated
Related Questions
Assume you are working for an SME operating in the microelectronics sector. You are required to plan a new product development project. This is an internal project, so it does not

Regions of operation: Applied voltages Mode E Forward active E C Saturation E > B

What is TSR? TSR: The TPA also as TSR stand for terminate and stay resident programs which remain in memory in an active state till activated by a hot-key sequence or other eve

Three Phase Induction Motors A three  phase induction rotor  consists  a stators  and a motor stator has balanced three  phase  winding. These windings  are distributed in the

Q. Explain the construction of depletion MOSFET? A slab of p-type material is formed from a silicon base and it is referred to as the substrate. It is the foundation upon which

Energy stored in a capacitor During charging process by capacitor, it will get energy. Energy is stored in static form. The voltage in capacitor will enhance from 0 volt to E v


Effective Mass The electrons' "wave-particle" motion in a lattice is not the same as that for a free electron, because of the interaction with the periodic potential of the

Figure shows the cross-section of an electrostatic problem with translational symmetry: a rectangular coaxial cable. The inner conductor is held at 10 volts and the outer conductor

Discuss important properties and uses of Mica and Mica Products. Mica and Mica Products - Mica is an inorganic material. This is one of the best insulating materials availa