synchronous gap (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 10 Jul 2007 18:44:55 -0700
From: Stephen A. Mathieson <sm@xxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: synchronous gap

I have yet to run my RSG is synchronous mode but it uses a technique you may
find interesting.

 

Regular old induction motors are cheaper and easier to obtain. I am using a
3 phase induction motor

driven by a variable speed AC drive. All you have to do to make it
synchronous is to put a PLL in the feedback loop.

An added benefit is that it allows for the gap to fire at whatever point
along the sine wave that you wish.

 

I have a 10 inch disk of ½” G10 and I have spun it as fast as 7500 RPM with
no problems.

 

The only drawback that I have found so far is that the induction motor must
be placed outside 

the magnetic field generated by the primary coil. If the motor is in the
primary’s magnetic field the AC drive trips due to

a current fault as it can no longer keep track of the current in the motor.

 

Good luck,

 

Stephen Mathieson