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

Describe in brief how email system works, Describe in brief how email syste...

Describe in brief how email system works Following is a simple description of how email system works: -  Sender composes a message (and attaches a file if required) and send

Aggregate technical and commercial loss, Aggregate Technical and Commercial...

Aggregate Technical and Commercial Loss It is unfortunate in that addition to T&D losses, there is also a loss in revenue because of non-realisation of billed demand which lea

Write a short note on heat sink, Q. Write a short note on heat sink For...

Q. Write a short note on heat sink For transistors handling small signals ,the power dissipated at the collector is small.Such transistors have little chances of thermal runawa

Estimate the required bandwidth using Carson''s rule, A 10-kHz tone is used...

A 10-kHz tone is used to frequency modulate a carrier; the peak deviation is 75 kHz. Use Carson''s rule to estimate the bandwidth.

For the given circuit determine voltage, Q. For the circuit shown in Figure...

Q. For the circuit shown in Figure, determine v out (t).

Linear components, A linear circuit component is one that has a linear I V ...

A linear circuit component is one that has a linear I V characteristic

Calculate the voltage gain, Using the BC548B BJT transistor amplifier biasi...

Using the BC548B BJT transistor amplifier biasing circuit of Lab 2 build an amplifier with the voltage gain of  |A V | = 30 v/v ± = 10%. Measure all necessary parameters of the amp

What is global positioning satellite, What is Global Positioning Satellites...

What is Global Positioning Satellites (GPS) Global positioning satellite (GPS) systems are used to determine exact location of a car, ship, airplane or any conveyance that trav

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