Permanent magnets, Electrical Engineering

Assignment Help:

Materials with 'hard' magnetic B/H characteristics often show a strong residual magnetism. This makes them suitable for making permanent magnets. If the ring material were magnetised, then the magnetised material itself will create a flux in the ring. No current carrying coil will be required.

1915_permanent magnets.png

 

For a permanent magnet, flux is produced by the alignment of magnetised domains within the material itself. (c.f earlier notes relating to residual magnetism in B/H curve).  In this case, the flux exists without the need for a coil, i.e. N.I = 0. Hence applying Ampere's Law results in:

 

1504_permanent magnet.png

Hence eqn 1 and the B/H curve must be simultaneously satisfied and to give the flux density and magnetic field strength in the magnetic material (and hence also the air gap)

 

1077_permanent magnet 1.png

 

 

from equation (1)  Bc/Hc=-Lc/Lgµ0         

 

which is slope of a straight line. The flux density and magnetic field in the magnetic circuit is given by the point at which eqn (1) cuts the B/H curve. Permanent magnets are widely used in transducers:- loud speakers, measuring meters, D.C. motors etc.

 


Related Discussions:- Permanent magnets

Explain hall effect, Explain Hall Effect. Hall Effect: If a current c...

Explain Hall Effect. Hall Effect: If a current carrying conductor is placed in a magnetic field, a voltage is produced that acts in the perpendicular direction to the current

Determine the electromagnetic power, A dc shunt motor runs off a constant 2...

A dc shunt motor runs off a constant 200-V supply. The armaturewinding resistance is 0.4, and the ?eld winding resistance is 100 . When the motor develops rated torque, it draws

Cycloconverter scherbius drive - motor control , Cycloconverter  Scherbius...

Cycloconverter  Scherbius Drive In this  drive  instead of dual controlled used in link  scherbius  drive one  phase  controlled  line commutated cyclconverter is used. This

Working of a negative clamping circuit, Q. Draw and explain the working of ...

Q. Draw and explain the working of a negative clamping circuit. The clamping network shown above is a negative clamping circuit that will clamp the input signal to a negative d

Bus organisation, Bus Organisation Set of  communication lines in micro...

Bus Organisation Set of  communication lines in microprocessor  which  carry  bits from microprocessor to  peripherals  ( memory  inputs ports  output  ports  and other chips

Briefly explain about wheatstone bridge, Q. Briefly explain about Wheatston...

Q. Briefly explain about Wheatstone Bridge? Null measurements are made with bridge circuits and related configurations. They differ from direct measurements in that the quantit

RC coupled amplifier, what is the reason for reduction in low frequency and...

what is the reason for reduction in low frequency and high frequency regions in the frequency response of an Rc coupled amplifier?

Load carrying capacities , Task a)    Investigate and describe the sign...

Task a)    Investigate and describe the significance of the following: i.    Slenderness ratio and buckling in columns ii.    Effective length of columns b) Explain Eu

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