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Old 03-19-2019, 01:11 AM
bistander bistander is online now
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Join Date: Apr 2015
Posts: 1,598

Originally Posted by Aaron View Post
Nobody said you're mistaken on this one point there but you like to wiggle around with your answers.

I'll ask something else...

What happens when you short a generator that is holding up to the laws you believe in?

A simple answer without the slippery talk is preferred.

And why does a generator do what it does when you short the output?

In a well designed generator, shorting the output will tend to bring the machine to a screeching halt. If the prime mover is strong enough to overcome the generator's strong torque opposing rotation, the generator will blow circuit protection or burn up from overload. Shorting the generator output causes very high currents which react with the magnetic field and produce torque according to Lorentz. Depending on the particular generator design other things may occur. Armature reaction may demagnetize the field and rotation could continue with severely diminished output. In a magnetic loose generator like is often the case with machines without proper magnetic circuits (backiron and such), the armature reaction will weaken the field such that the machine will not produce excessive torque or possibly not even overheat, but rather continue to rotate and generate using the armature as its load.

This is easy to demonstrate for yourself. Most would have a PM DC 2-wire motor around the workbench. I just tried this with a MY6812 sitting in front of me. You would agree, I hope, this motor or similar can be used as a generator. So first, with it no-load (nothing connected to the terminals), twist the shaft by hand. You feel a little resistance to the twisting, but it is possible to get it up to a fairly rapid rotation. Now short circuit the terminals. Twist again. At very slow rotation, little difference is felt. But try an attempt to give it a very quick spin. You cannot rotate it very fast at all.


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