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

Express the waveform of the staircase type, Q. Express the waveform of the ...

Q. Express the waveform of the staircase type shown in Figure as a sum of step functions.

#titl optimal power flow , to get PV curve i want optimal power flow progra...

to get PV curve i want optimal power flow program in matlab

MATLAB, Future scope on MATLAB in India

Future scope on MATLAB in India

Show the procedure of hex to decimal conversion, Q. Show the procedure of H...

Q. Show the procedure of Hex to Decimal Conversion? To convert from the Hex to the Decimal, multiply the value in each position by its hex weight and add each value. Using the

Framework for indicators in electricity sector, Framework for Indicators in...

Framework for Indicators in Electricity Sector A framework has been developed and a set of core indicators for electricity Sector has been proposed. In the first example, mapp

Is the mosfetoperating in the active region, Q. A depletion MOSFET is given...

Q. A depletion MOSFET is given to have large V A , V P = 2.8V, I DSS = 4.3 mA, v DS = 4.5V,and v GS = 1.2V. (a) Is theMOSFEToperating in the active region? (b) Find iD.

Explain idiv instructions in 8086 family, Explain IDIV instructions in 80...

Explain IDIV instructions in 8086 family with example and their effect on flag. IDIV: It used to divide a 16-bit signed number with an 8-bit signed no. or 32 bit signed numb

Role of electricity regulatory commission in kpi, Role of Electricity Regul...

Role of Electricity Regulatory Commission in KPI The new Electricity Act, 2003, has empowered Electricity Regulatory Commission (ERC) to play an extremely decisive role in all

Jfet ampli?er circuit, Q. For the CS JFET ampli?er circuit of Figure, R D ...

Q. For the CS JFET ampli?er circuit of Figure, R D = 2k and R L = 3k. The JFET with ro = 15 k has a voltage gain A v1 =-4.5 when the entire source resistance is bypassed. Fin

Explain common emitter configuration, Q. Explain Common emitter configurati...

Q. Explain Common emitter configuration? Common emitter configuration: In this circuit the emitter is common to both input and the output.Such a configuration is also known as

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