Induced voltage and inductance, Electrical Engineering

Experiments conducted by Faraday and others using current carrying coils resulted in 'The Laws of Electromagnetic Induction' which state:

1)  'If the magnetic flux threading through an electrical circuit changes, then an e.m.f. is induced in the circuit'.
 
2) 'The magnitude of the induced e.m.f. is proportional to the rate of change of the magnetic  flux  through the     circuit'. (Faraday's Law)

3) 'The induced e.m.f. has a direction such that  the  current  which  flows  (or  would flow if the circuit is completed) gives rise to magnetic effects that oppose the effects producing it'.(Lenz's Law)

 

These principle are widely used to convert mechanical power into electrical power - e.g the alternator.These are general principles that are true however the change in flux is produced. It may be due to:

 

  •  moving magnets near the coil
  •  changing the current  flowing  in a nearby coil
  •  changing the current within the coil itself
  •  relative movement between the coil and the magnetic field.

The polarity of the emf produced will act to try to oppose the change causing it. If it is due to an external flux change, the induced emf will drive a current in the coil that itself produces a flux that opposes the change due to the external influence.

If the flux change is due to a change in the current within the coil, the emf generated will act to oppose the change in current. This is called a 'back emf'.
 
Faraday was able to quantify the effect and expressed the observations mathematically as:

v=-Ndq/dt   (Faraday's Law)

 where N is the number of turns on the coil and dq/dt  is the rate of change of flux threading the coil. Effectively, each turn  generates a back emf equal to dq/dt  and since the emfs produced by each turn are in  series, the total back emf is N times that of
each turn considered separately

 

Posted Date: 8/22/2012 5:32:52 AM | Location : United States







Related Discussions:- Induced voltage and inductance, Assignment Help, Ask Question on Induced voltage and inductance, Get Answer, Expert's Help, Induced voltage and inductance Discussions

Write discussion on Induced voltage and inductance
Your posts are moderated
Related Questions
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

Can someone please guide me on how to compute a nash equilibrium in matlab

Low and high resistivity materials and their applications

draw the gain frequency response of an RC coupled circuit? discuss fall in gain at very low and very high frequencies?

a) Describe Schmitt trigger with the help of transfer characteristics. b) Also get the expression of hysteresis voltage VH and output waveform for sinusoidal input signal

Voltage  and Frequency Control Methods In this  control  method the ratio of voltage  to frequency is kept constant so that the  flux  remains  constant. The voltage  at varia

Q. What are frequency response curves? How are they made? Every amplifier has a frequency-response curve associated with it. They provide a "picture" of the performance of an a

Active-mode NPN transistors in circuits Figure:  Structure and use of NPN transistor. Arrow according to schematic. The figure opposite is a schematic presentation

Q. Explain about Direct-current machines? Generally speaking, conventional dc generators are becoming obsolete and increasingly often are being replaced by solid-state rectifie

Role of Bureau of Energy Efficiency The role of the Bureau of Energy Efficiency is to: Ready standards and labels of appliances and equipment; Develop a list