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

How to remove the LSB from the audio recording?, Using the audiorecorder() ...

Using the audiorecorder() function in MATLAB, make a recording of your voice. Use a sample rate of 8kHz, 16 bits per sample, and aim to record around 2 seconds worth. Quantize the

Find the current source, Q. Consider the circuit shown in Figure. (a) Gi...

Q. Consider the circuit shown in Figure. (a) Given v(t) = 10e -t V, find the current source is(t) needed. (b) Given i(t) = 10e -t A, find the voltage source v (t) needed.

Why common collector amplifier is known aa emitter follower, Q. Why a commo...

Q. Why a common collector amplifier is called an emitter follower?         When the input voltage goes through its positive half cycle, the output voltage is also seen to go th

Determine the voltage in given circuit, Q. In the circuit shown in Figure w...

Q. In the circuit shown in Figure with an ideal op amp, find v o as a function of v a and v b .

Transformes, how to calculate the sending line voltage

how to calculate the sending line voltage

Assembly language instructions, Normal 0 false false false ...

Normal 0 false false false EN-IN X-NONE X-NONE

Comparison with vacuum tubes, Comparison with vacuum tubes: Prior to t...

Comparison with vacuum tubes: Prior to the growth of transistors, vacuum (electron) tubes (or in the UK (United Kingdom) "thermionic valves" or just "valves") were the major a

Frequency response of your amplifier, a) What is meant by frequency respons...

a) What is meant by frequency response and how would you check the performance of your amplifier? b) Calculate the Voltage Gain of your amplifier at a range of frequencies suffic

Conveyor, The FESTO conveyer consists of 600mm belt driven by a 24V d.c. mo...

The FESTO conveyer consists of 600mm belt driven by a 24V d.c. motor at a rate of 13 seconds per metre. A relay on the FESTO panel controls the motor operation and is wired for sou

Find the corresponding energy, Q. Consider a pair of coupled coils as shown...

Q. Consider a pair of coupled coils as shown in Figure of the text, with currents, voltages, and polarity dots as indicated. Show that the mutual inductance is L 12 = L 21 = M by

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