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

Define some applications of digital counters, Define some Applications of D...

Define some Applications of Digital Counters? Digital counters are extremely useful in many applications. They can be effortlessly found in digital clocks and parallel-to-seri

Weighted resistor and the r-2 r ladder d/a converters, Q. What is the basic...

Q. What is the basic difference between the weighted resistor and the R-2 R ladder D/A converters?

Statics, a mass of 20 kg is lifted u p to the roof of a cliff 100 m high.de...

a mass of 20 kg is lifted u p to the roof of a cliff 100 m high.determie Ep of the mass while it is at the top

Dielectric heating - stepper motor , Dielectric Heating Dielectric  l...

Dielectric Heating Dielectric  losses  occur in  insulating materials. These are same  as hysteresis losses  in magnetic materials. When  an alternating  electric  field  is a

Power system engineering, A three-phase transposed line is composed of one ...

A three-phase transposed line is composed of one ACSR conductor per phase with flat horizontal spacing of 11 meters as shown in Figure (a). The conductors have a diameter of 3.625

Neural network, solve problem by neural network using matlab code

solve problem by neural network using matlab code

Illustrate core losses in magnetic core material, Q. Illustrate Core Losses...

Q. Illustrate Core Losses in magnetic core material? Iron-core losses are usually divided into two components: hysteresis loss and eddy-current loss. The former is proportional

Explain radio and television broadcasting, Q. Explain Radio and Television ...

Q. Explain Radio and Television Broadcasting? Radio (AM and FM) and television broadcasting are the most familiar forms of communication via analog transmission systems. The re

Find the duty ratio and neglecting friction and windage, A 440-V, 60-Hz, si...

A 440-V, 60-Hz, six-pole, wye-connected, wound-rotor induction motor with a full-load speed of 1170 r/min has the following per-phase parameters referred to the stator:R 1 = R' 2

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