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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
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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...
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