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

For sign flag - return instructions, For sign flag  RP ( Return on ...

For sign flag  RP ( Return on Plus ) and RM ( Return on no minus ) Instructions RM returns from the subroutine  to the calling program if sign flag is set  (S=1). The in

Configured the dual processor architecture, Configured dual processor archi...

Configured dual processor architecture  In centralized SPC, dual processor architecture can be configured to operate in following one of three modes: 1.  Standby mode: In

Determine the low-pass filter and amplitude spectra, Q. Let a square-wave v...

Q. Let a square-wave voltage source having an amplitude of 5V, a frequency of 1 kHz, a pulse width of 0.5 ms, and an internal source resistance of 50  be applied to a resistive lo

Smart parking system, Design a smart park system using Iot sensors to udate...

Design a smart park system using Iot sensors to udate stautus to a server ?

Explain the different types of polarizations, Explain the different types o...

Explain the different types of polarizations. Polarizations are of three types. i. Electric polarization ii. Ionic polarization. iii. Dipolar polarization.

How linear sweep voltage is generated, Q. With a suitable block circuit, sh...

Q. With a suitable block circuit, show how linear sweep voltage is generated ? The above figure shows a basic sweep waveform generator. The switching action of the switch

Spectrum analyzer, Problem statement: A specialized piece of laboratory te...

Problem statement: A specialized piece of laboratory test equipment, called a spectrum analyzer,will be placed on a mobile push cart. The spectrum analyzer measures the amplitude

Describe 74ls139 memory decoder, Describe 74LS139 memory decoder. The 7...

Describe 74LS139 memory decoder. The 74LS139 is a dual 2-to-4 line decoder. This contains two separate 2-to-4 line decoders - all with its address, output and enable connection

A 450 ns eprom won''t work directly with a 5mhz 8088, A 450 ns EPROM won't ...

A 450 ns EPROM won't work directly with a 5MHz 8088.Why? Explain. While the 8088 is operated along with a 5 MHz clock, it permits 460 ns for the memory to access data. Due to t

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