Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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
Cm =machine constant
The equivalent circuit representation of an electrical generator is:
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 machinesAn 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
A three-phase, 220-V, 60-Hz, four-pole, wye connected induction motor has a per-phase stator resistance of 0.5 . The following no-load and blocked rotor test data on the motor are
input impedence
Which potentiometer do I need to control; 6v 2amps dc?
function of a commutator in a DC motor
Question 1 Explain how switching systems are classified Question 2 Explain the function of pulse dialing in rotary dial telephone Question 3 Explain the functioning of crossba
Q. What do you mean by Phase Sequence? It is standard practice in the United States to designate the phase A-B-C such that under balanced conditions the voltage and current in
Distribution: This has been recognized as the most critical segment of the electricity business. Here the NEP calls for proper restructuring of distribution utilities for achi
why Vout begins to decrease ...
Q. Determine briefly subscriber loop system. Give some technical specification for subscriber lines. Ans: Subscriber Loop System: Each subscriber in a telephone network is
Q. Determine the equivalent capacitance at terminals A-B for the circuit configurations shown in Figure.
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd