Back EmF? Please Explain! (1 Viewer)

[SmileyCam]

Back EmF? and a bit more... Please Explain!

Assessment task:
Explain:
Lenz's Law
Eddy Currents
Back EmF

I understand the first 2 but I don't get Back EmF.
Please help >.<

 

[acmilan]

Whilst a motor turns in magnetic field there is relative movement between the field and armature which creates an emf as shown by Faraday. Lenz's Law shows that this emf will be in a direction as to oppose the cause and hence it travels opposite to the current flowing through the motor giving it the name back emf.

 

[SmileyCam]

another thing

also:

Implication of the above 3 to motors, transformers and any other electrical appliances

I've got motors/transformers, just need a couple of extras, any help is much apprecieated

by the bye, thanx acmilan

 

[acmilan]

Lenz's law: assists in determining direction of induced currents in motor and transformer

Back emf: means that motors require variable resistors so that the operating current in the motor does not get too high, could result in danger etc

Eddy currents: reduce transformer efficiency, need to be reduced by laminating iron core and placing insulation between layers

 

[SmileyCam]

Thanx,
What about any other electrical applications (other than motors and tranformers)?

 

[acmilan]

Induction cookers

 

[xiao1985]

Induction cookers

magnetic breaking =p

 

[SmileyCam]

nice try but those 2 are a different part of the assignment (the only other part I haven't mantioned is the bibliography so any more suggestions will probably be good),

so any more that u can think of?