Back EMF

[PoorFish]

Sorry P Feeney if I have confused matters for you

.Cant confuse any more than I am already

I think the fact that it just happens in coils is ok for the moment

what was confusing me was the actual facts of how it is produced

i.e. the fact that the magnetic field produces a second emf

??????

thanks again all

 

[SPECIAL LOCATION]

For you SL.YouTube - Godfather - Horse Head

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I am honoured you went to the trouble of posting that link!

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[SPECIAL LOCATION]

.Cant confuse any more than I am already

I think the fact that it just happens in coils is ok for the moment

what was confusing me was the actual facts of how it is produced

i.e. the fact that the magnetic field produces a second emf

??????

thanks again all

An electric current in a coil of wire generates a magnetic field.

(placed next to a fixed magnet, opposing magnetic fields cause movement thus principal of a motor)

and vise-versa

A magnet moving though a coil of wire generates an electric current.

(spin a coil next to fixed magnet, current induced, principal of generator or dynamo)

As the two above principals are opposite to each other..

a motor initially powered will move..

once moving can actually generate power back down the coils..

Reverse or BACK ELECTROMOTIVE FORCE {back EMF}

A DC current switching on & off can be considered as part of an AC cycle..

An inductor is a coil of wire which can generate a magnetic field..

if DC powered fixed magnetic poles,

if AC alternating magnetic poles.

Its all down to INDUCED MAGNETIC Fields..

coil the wire up magnetic field gets bigger.

bigger magnetic fields can induce bigger emf back into cable!

or something like that!

 

[PoorFish]

Thanks mr Special Location

Thats a very good explanation you have given me there.

Again I just need to digest it for a while.

However is Back EMF the same as Inductive reactance

 

[SPECIAL LOCATION]

Thanks mr Special LocationThats a very good explanation you have given me there.

Again I just need to digest it for a while.

However is Back EMF the same as Inductive reactance

{its 0:30am + Guiness DrinkGuiness Drink, but i will give it a shot for starters... I may regret this tomorrow! }

they are related...

The Inductive reactance is the opposition to AC current flow, relating to the build up of magnetic fields producing an emf that resists the flow of the current though the device.

Also the Capacitive reactance, at lower frequency blocks current flow.. higher frequency less opposition to current flow..

resistive, capacitive & inductive elements all work together to give the Impedance of an AC circuit.

The inductive & capacitive element's are called reactance rather than Back emf.

 

[PoorFish]

So its like the equivilant of back emf for current??!!??