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

Fourier deconstruction, Find the Fourier series as far as the third harmoni...

Find the Fourier series as far as the third harmonic, to represent the periodic function y, given by the values in the following table. x 0 o 30

Illustrate the photo-conductive cell, Illustrate in detail digital encoders...

Illustrate in detail digital encoders. Illustrate the following with their application: Photo-conductive cell Photo-voltaic cell

What are synchronous decade counters, What are Synchronous Decade Counters?...

What are Synchronous Decade Counters? Alike to an asynchronous decade counter, the synchronous decade counter counts from 0 to 9 and then recycles to 0 again, This is done by

Determine vout and the power supplied, Q. An operational amplifier stage is...

Q. An operational amplifier stage is typically represented by the circuit of Figure. For the values given, determine V out and the power supplied by the 2.5-V source.

Installed in circuit board, Can we measure the resistor if it is installed ...

Can we measure the resistor if it is installed in circuit board? Ans) You can calculate a resistor in a circuit but the circuit will most likely affect the value read (general

Can you show the decimal to octal conversion, Q. Can you show the Decimal t...

Q. Can you show the Decimal to Octal Conversion? To convert decimal to octal is somewhat more difficult. The usual method to convert from decimal to octal is repeated division

A, A microstrip antenna system operating at 915MHz must be designed using R...

A microstrip antenna system operating at 915MHz must be designed using Rogers RO3010 substrate with the thickness of 0.635mm.

Desirable requirements of a generic photo-detector, Question : a) Stat...

Question : a) State six desirable requirements of a generic photo-detector. b) A gallium arsenide pin photo-diode has an intrinsic layer of width 1 μm. The diode is revers

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