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

Construct the corresponding transfer function, Consider the following IIR f...

Consider the following IIR filter. The initial input data sequence is given by x n = [10 15 20 15 8 6 9 0 0 0] Construct a table that shows the corresponding signal values at

Subtract registers and borrow from accumulator, Subtract Registers and Borr...

Subtract Registers and Borrow from Accumulator The  contents of the  register  and borrow  flag  are subtracted from   the contents of the accumulator and the  result is  store

Load balancing and load management, Load Balancing and Load Management ...

Load Balancing and Load Management It has been observed in which the load on all three phases of a distribution line and between the feeders is not balanced. This output in in

Find load resistance and voltage, Q. Find load resistance and voltage? ...

Q. Find load resistance and voltage? Let the amplifier block be connected to a current source at the input terminals, as shown in Figure(a), and to a load resistance R L at it

Compute the maximum flux passing through the coil, Q. The 50-turn coil in t...

Q. The 50-turn coil in the configuration of Figure is rotated at a constant speed of 300 r/min. The axis of rotation is perpendicular to a uniform magnetic flux density of 0.1 T. T

TRANSISTOR BIASING CIRCUITS, HOW TO FIND THE OPERATING POINT OF THE TRANSIS...

HOW TO FIND THE OPERATING POINT OF THE TRANSISTO IN A COLLECTOR TO BASE BIAS CIRCUIT

What do you mean by negative impedance converter, Q. What do you mean by Ne...

Q. What do you mean by Negative Impedance Converter? The op-amp circuit of Figure causes a negative resistance R in between the input terminal and ground. In the more general

Society in engineering, Cite a specific example in which the engineer must ...

Cite a specific example in which the engineer must provide maximum efficiency for a given cost

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