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

Speed control of dc series motor - motor control , Speed Control of DC Seri...

Speed Control of DC Series Motor A half  wave  circuit  for the  speed  control of DC  series motor is  shown in figure and corresponding wave from  is shown  in figure  consis

What is the voltage controlled resistance region, Q. What is the Voltage co...

Q. What is the Voltage controlled resistance region?  In this region the JFET can actually be employed as a variable resistor whose resistance is controlled by the applied gate

Electrical distribution system, 1. Name the three parts of a programmable l...

1. Name the three parts of a programmable logic controller (PLC) and explain why the PLC is preferred by designers over electromechanical relays. 2. Medium-voltage circuit break

Logically and the contents of memory, Logically AND the contents of memory ...

Logically AND the contents of memory Contents of memory  location,  whose address is specified by HL register pair are logically AND with the  contents  of the accumulator. The

What are the basic operations of a computer, What are the basic operations ...

What are the basic operations of a computer? The basic operations are READ and WRITE.

SUPERPOSITION THEOREM, CONCLUSION IN BRIEF OF SUPERPOSITION IN ASSIGNMENT

CONCLUSION IN BRIEF OF SUPERPOSITION IN ASSIGNMENT

Explain state transition diagram, a. Explain State Transition Diagram and d...

a. Explain State Transition Diagram and define the various SDL symbols used in state transition diagram. b. Draw the signal exchange diagram for a local call used to show the se

Describe the magnetic effects of current, 1.   Describe the magnetic effe...

1.   Describe the magnetic effects of current? ( to achieve a pass grade, describe the magnetic effect of current) 2.   Complete the diagram to show the direction of mo

2365-305 Electrical systems design TASK A, Hi, I need help with this assign...

Hi, I need help with this assignment. Is this assignment something you can help me with?

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