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

Sources of power dissipation in cmos logic, Describe the three main sources...

Describe the three main sources of power dissipation in CMOS logic. Hence calculate the power dissipated in a CMOS ASIC of 40,000 gates operating at a frequency of 133MHz with a s

Determine the range of analog output voltage, Q. For the 4-bit D/A converte...

Q. For the 4-bit D/A converter of Figure with V ref =-5 V, determine the range of analog output voltage and the smallest increment. Ans. The binary input range is from 0

What is voltage multiplying dacs, What is Voltage Multiplying DACs? Mul...

What is Voltage Multiplying DACs? Multiplying DACs function on the principle of producing a weighted sum analog signal where the sum is proportional to the digital input signal

Determine the admittance of the parallel combination, Q. The voltage across...

Q. The voltage across a parallel combination of a 100- resistor and a 0.1-µF capacitor is 10 cos(5000t +30°) V. Determine the admittance of the parallel combination and find the c

Active filter design, Design a wide band pass filter with cut-off frequency...

Design a wide band pass filter with cut-off frequency f L = 400 kHz, f H = 600 kHz, and a pass-band gain = 10. The roll-off rate at the cut-off frequency should be at least 4

Communication, can I get matlab code for out of band radiation reduction of...

can I get matlab code for out of band radiation reduction ofdm system

Matlab antenna diversity, please I need help in matlab to program complex e...

please I need help in matlab to program complex expression in antenna diversity please

Number systems, Number Systems Various number systems  are decimal ( us...

Number Systems Various number systems  are decimal ( used by human beings) binary ( used by digital  systems) octal  and hexadecimal (used to represent  binary numbers in small

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