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

Aerodynamic principles & aircraft design, Define the aircraft axes & degree...

Define the aircraft axes & degrees of freedom. Analyse the different maneuvers that can be done by an aircraft.

Logistical management - gis applications, Logistical management - Gis appli...

Logistical management - Gis applications: Using GIS also allows a radical improvement in daily work management practices - such as planning new installations, scheduling opera

Input output operations , Input Output Operations Many times microproc...

Input Output Operations Many times microprocessor has to  accept data  from input port and send data to  output  port to  interact with the  real world. Input  port is  tri st

Increment contents of register - inr instruction , Increment contents of Re...

Increment contents of Register Content  of register  are   incremented  by one and the  results  is stored  in the same  register R. It is an exceptional  case in which  accumu

Characteristics of an n-channel enhancement mosfet, Q. Find idealized expre...

Q. Find idealized expressions for the active and ohmic states and sketch the universal characteristics of an n-channel enhancement MOSFET operated below breakdown.

add instruction, ADD Instruction This  instruction use to add  content...

ADD Instruction This  instruction use to add  contents of any  register or memory  location with the  contents of accumulator. There are two  formats for ADD  instruction to ad

Limitor, What is limitor.. how it works

What is limitor.. how it works

Cmc complement carry instruction , CMC Complement Carry Instruction Th...

CMC Complement Carry Instruction This instruction complements  the carry  flag i .e   if the carry flag  is 1 before the execution of this  instruction it will be reset and if

Explain diffusion, Explain Diffusion. Diffusion : Though, the mobili...

Explain Diffusion. Diffusion : Though, the mobility of the carriers in a semiconductor is greater than the electrons in metals, the conductivity in the former is much less t

First quadrant or class a chopper, First Quadrant or Class A chopper A ...

First Quadrant or Class A chopper A chopper  two mode operation of class  A chopper  can be explained as follow.

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