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

Find the maximum radiation intensity, Q. An antenna has beam widths of 3° a...

Q. An antenna has beam widths of 3° and 10° in orthogonal planes and has a radiation ef?ciency factor of 0.6. Find the maximum radiation inten- sity if 1 kW is applied to the anten

List out the reasons for automation, Describe the term (i) Automation ...

Describe the term (i) Automation (ii) Automated lines 04 List out the reasons for automation and discuss in detail the process of work part transport.

Electricity and gas hazards, Electricity beyond doubt is very useful and es...

Electricity beyond doubt is very useful and essential for us; but if dealt with carelessly, it can prove to be very fatal. It is compulsory for a laboratory assistant to be sure of

Advantages of expert system, Advantages of Expert System The system, on...

Advantages of Expert System The system, once set up, requires to be tested employing data with known outcomes to see if it functions correctly. If it's being used to diagnos

What is digital system components, Q. What is Digital system components? ...

Q. What is Digital system components? The reason that digital systems are so inexpensive and yet so powerful is that they consist of very  large numbers of just a few building

Advantages and disadvantages of aluminium, Discuss the advantages and disad...

Discuss the advantages and disadvantages of aluminium as compared to copper as a conductor of electricity. Advantages: Aluminium as a conductor of electricity as compared co

Briefly explain about laplace transform, Q. Briefly explain about Laplace t...

Q. Briefly explain about Laplace transform? Many commonly encountered excitations can be represented by exponential functions. The differential equations describing the network

Telecommunication principles, Draw the block diagram of TDM-PCM system. Exp...

Draw the block diagram of TDM-PCM system. Explain each block. Calculate the bit rate at the output of this system

Which alloy is used for making heater & thermocouple element, Give the name...

Give the names of four alloys along with their composition, which are used for making heater and thermocouple elements. Constantan or Eureka {(55 to 60 percent) Cu, (45 to 40 p

State the drawbacks of in band and out band voice signalling, a. Enlist the...

a. Enlist the benefits and drawbacks of in band and out band voice signalling? b. Describe Channel Associated mode, Channel Non-Associated mode and QuasiAssociated mode of commo

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