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

FET, shockely equation?

shockely equation?

Determine the armature current and power factor of the motor, A three-phase...

A three-phase, wye-connected, 2300-V, 60-Hz, round-rotor synchronous motor has a syn- chronous reactance of 2 per phase and negligible armature resistance. (a) If the motor tak

Find the minimum rate of sampling, Find the minimum rate of sampling that m...

Find the minimum rate of sampling that must be used to convert the message into digital form: (a) If an audio message has a spectral extent of 3 kHz. (b) If a television sign

Calculate the total power supplied to the divider circuit, There is often a...

There is often a need to produce more than one voltage from a single supply using a voltage divider. For example, the memory components of many personal computers require voltages

Honer, Can I have formulas for calculation of 50TN seting on 33KV overhead ...

Can I have formulas for calculation of 50TN seting on 33KV overhead line

Load resistor , a) Include a Smoothing Capacitor to the Rectifier circuit a...

a) Include a Smoothing Capacitor to the Rectifier circuit and calculate the Output Voltage and Frequency b) Include a 47Ω Load Resistor and sketch the schematic diagram of the c

Electronic and electrical measurement CRO., Describe the construction and w...

Describe the construction and working of atleast two types of storage CRO

Find out the output if resistance, Q. The input to the differentiator circu...

Q. The input to the differentiator circuit is a sinusoidal voltage of peak value 5mv and frequency 1kHZ. find out the output if R=100K and C=10^-6F Solution. The equation

Illustrate about full duplex transmission, Q. Illustrate about Full Duplex ...

Q. Illustrate about Full Duplex Transmission? Full Duplex Transmission Data can travel in both directions simultaneously. There is no need to switch from transmit to receive

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