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Old 02-24-2009, 07:20 PM
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nilrehob nilrehob is offline
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Join Date: Nov 2008
Location: Sweden
Posts: 689
This is my (latest) conclusion about the different kinds of EMF:

* back EMF appears when a coil is building up its magnetic field and is opposite to the applied current
* forward EMF appears when the magnetic field in a coil collapses and generates a current in the same direction as the interrupted current
* counter EMF is generated in dc-motors as the motor is also a generator, but is usally called back EMF

Just as a capacitor can be used to smoothen out variations in voltage, a coil can be used to smoothen out variations in current.
If You shorten a capacitor You get a current rush, if You shorten a coil You get a voltage spike.
A Bedini motor cannot work as a generator and therefore do not generate any counter EMF, but the coil in it first generates back EMF when the transistor opens and then forward EMF (as a spike) when it closes.

If this is correct it means that I'm wrong in my videos, I'm not trying to capture the back EMF but rather the forward EMF.

...I think...
Hob Nilre
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