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

Analog circuit, What is the disadvantages of diodes as a series element in ...

What is the disadvantages of diodes as a series element in a clipper?

Transformers, What is the difference between “Insulating,” “Isolating,” and...

What is the difference between “Insulating,” “Isolating,” and “Shielded Winding” transformers? Can Acme Transformers be reverse connected? . Can Transformers develop Three Phase po

Find the resistor values of rc, Apply the rule-of-thumb dc design presented...

Apply the rule-of-thumb dc design presented in this section for a silicon npn BJT with β = 70 when the operating Q point is defined by I CQ = 15 mA and I BQ = 0.3 mA, with a dc s

Find the small-signal equivalent circuit parameters, Given that a BJT has β...

Given that a BJT has β = 60, an operating point defined by I CQ = 2.5 mA, and an Early voltage V A = 50 V. Find the small-signal equivalent circuit parameters g m , r o , and rπ.

Singular value decomposition, Singular Value Decomposition (i) initial...

Singular Value Decomposition (i) initialize a 2x2 matrix m=[4 0.5;0.5 7]  Factorize the matrix with SVD [u d v]=svd(m) How the matrix u and v differ? Why is that?

Compute current in given the circuit configuration, Q. Consider the circuit...

Q. Consider the circuit configuration shown in Figure. Let V i = 1V, R 1 = 1000, R 2 = 2000, and A = 3. (a) Compute i 2 . (b) If R 1 changed to 500 , recompute i 2 .

Digital control system, block diagram of digital control system and explain...

block diagram of digital control system and explain each block

Briefly explain about wye-delta transformation, Q. Briefly explain about Wy...

Q. Briefly explain about Wye-delta transformation? Certain network configurations cannot be reduced or simplified by series-parallel combinations alone. In some such cases wye-

Wireless and communication, With a maximum excess delay of and a chip durat...

With a maximum excess delay of and a chip duration of , the multipath components fall in delay bins. This means that we experience leakage of energy between chips and the channel i

Design and build a circuit board, Devise a "green" design to improve the el...

Devise a "green" design to improve the electrical plan of a room in your home. How might you reduce electricity use in your home. Initiate and plan 1. Select two rooms in y

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