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

Measure and set frequency by using an oscilloscope, 1. Introduction : ...

1. Introduction : Theory: Frequency is the number of occurrences of a repeating event per unit time. It can also be defined as the number of repetitions (cycles) of a w

Plot the waveforms of the inductor current, Q. The current through a 2.5-mH...

Q. The current through a 2.5-mH indicator is a damped sine given by i(t) = 10 e -500t sin 2000t. With the aid of MATLAB, plot the waveforms of the inductor current i(t), with v

Composition of fet, Composition of FET The FET (field-effect transisto...

Composition of FET The FET (field-effect transistor) can be constructed from several semiconductors, silicon being by far the most common. Several FETs are made with conventio

Planning and research in power system, Q. Planning and Research in power sy...

Q. Planning and Research in power system? Energy research worldwide is assuming top priority, in particular because of economic, en - vironmental, and resource constraints. DOE

Find current-equivalent resistor reductions for the network, Q. Find the cu...

Q. Find the currents I x using current division and equivalent resistor reductions for the networks given in Figure.

Electricity, Describe the nature of electricity

Describe the nature of electricity

Ohm, what is ohm?

what is ohm?

Interrupt signals - pins and signals , Interrupt Signals There are five...

Interrupt Signals There are five  interrupt  signals in 8085 microprocessor.  These  signals  are used to inter rut the  current  program  under  execution and  transfer the ex

Biasing, Biasing: Bipolar transistor amplifiers have to be properly bi...

Biasing: Bipolar transistor amplifiers have to be properly biased to operate properly. In circuits made up with individual devices (discrete circuits), biasing networks contai

Diode, positive diode and negtive diode cliping

positive diode and negtive diode cliping

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