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

Electronics, determine mimimum SOP for the following swiching funcion using...

determine mimimum SOP for the following swiching funcion using K-map: F(x1,x2,x3,x4)=Summationof m(4,6,8,10,11,12,15)+DC(3,5,7,9)

In given block diagram find geq, Q. Show that the block diagram of Figure c...

Q. Show that the block diagram of Figure can be reduced to the form of Figure. Find G eq (s) and H eq (s).

Obtain plots by using probe, Q. A dc source is connected to a series RLC ci...

Q. A dc source is connected to a series RLC circuit by a switch that closes at t = 0, as shown in Figure, with initial conditions. For the values of R = 20, 40, and 80 , solve for

Explain working of cardiac pacemaker, Q. Explain working of Cardiac Pacemak...

Q. Explain working of Cardiac Pacemaker? When blockage occurs to the biological signals that stimulate the heart to beat, the application of electric pacemaker pulses forcing t

What is extended memory system, What is XMS? XMS: The memory system is ...

What is XMS? XMS: The memory system is splits in three major parts as: system area, XMS (extended memory system) and TPA (transient program area). The kind of microprocessor in

Explain telephone hand set and it’s working, Q. Explain Telephone hand set ...

Q. Explain Telephone hand set and it’s working ? A standard telephone set is comprised of a transmitter, a receiver and electrical network for equalization, associated circ

Differentiate thermoplastic & thermosetting plastic material, Classify plas...

Classify plastic materials into two categories describe their important properties and give two examples of each. Plastic materials can be categorized in thermoplastic and ther

Break over voltage of finger voltage - thyristor , Break over  voltage of...

Break over  voltage of Finger Voltage   The  minimum  forward voltage  when the gate  is opened  at which SCR  starts  conducting  heavily is called  the break over  voltage. To

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