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
Design and draw a circuit using the cascade system to operate two cylinders (A and B) which, on the operation of a start valve, produces the sequence A – B + B – A+. The cylinders
Q. Show a block diagram of a 4-bit, parallel-input shift-right register and briefly explain its operation.
For the RC phase-shift oscillator if c=1pF and R=10K determine the value of Rf
Active-mode PNP transistors in circuits: In the figure, the arrows showing current point in the direction of conventional current - the flow of electrons is in the opposite di
give the expression
What is resistivity? Resistivity of a material may be explained as the resistance of the material having unit length and also unit cross sectional area. Unit of it is ohm-m.
GIS Based Mapping of Electrical Network: You have learnt in which the Geographic Information System is a system of mapping of the complete electrical network. The question we
Ferromagnetic materials have some 'residual magnetism' even when the current (proportional to H) is zero. Material with strong residual magnetism are useful for making permanent ma
a) Provide pertinent summary of the basic principles behind ECG monitoring b) Using MATLAB, provide plots of the "clean" and "noisy" ECG signals. Investigate the spectral es
Q. Use of Speaker? Speaker:Basically speaker is the receiver for telephone. Speaker converts electrical signals received from local loop to acoustical signals(sound waves) that
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