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

Show binary to octal conversion, Q. Show Binary to Octal Conversion? It...

Q. Show Binary to Octal Conversion? It is simple to convert from an integer binary number to octal. This is accomplished by: Break the binary number into 3-bit secti

Determine the remaining voltages and currents, Q. Some element voltages and...

Q. Some element voltages and currents are given in the network con?guration of Figure. Determine the remaining voltages and currents. Also calculate the power delivered to each ele

., ABOUT ASSIGNMENT ON MAGNETIC INDUCTION NEAR A LONG WIRE

ABOUT ASSIGNMENT ON MAGNETIC INDUCTION NEAR A LONG WIRE

What is piconet, A collection of devices connected by Bluetooth technology ...

A collection of devices connected by Bluetooth technology in an ad hoc fashion.

#title. Armature winding, Why is an armature winding in d.c machine called ...

Why is an armature winding in d.c machine called closed winding.

How can a jfet be used as a constant current source, Q. How can a JFET be u...

Q. How can a JFET be used as a constant current source? Explain from the drain characteristics. As the VDS voltage is increased from 0 to a few volts, the current will increase

What do mean by flow of electron, Flow of electrons - Electrons flow down a...

Flow of electrons - Electrons flow down a wire that is what current, is. Good conductors like copper and silver and aluminum have free electrons in their outer shells, and they jum

What do you mean by instrument transformers, Q. What do you mean by Instrum...

Q. What do you mean by Instrument transformers? These are generally of two types, potential transformers (PTs) and current transformers (CTs). They are designed in such a way t

Vital parameters of regulator quality, Vital parameters of regulator qualit...

Vital parameters of regulator quality: 1. The output voltage's temperature coefficient of is the change in output voltage with temperature (perhaps averaged over a certain tem

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