Hey Stephen...
A rather rough manner to set up a sync rotory gap is as follows
1. turn off the rotory gap align the electrodes
2. turn variac to 0 and turn on coil raise variac voltage slowly
untill gap fires, mark the seting on the variac
3. turn on rotory gap and rest variac to 0 turn on coil turn variac to
setting you had to mark
if rotory is "aligned", gap should fire. If it doesnt fire, rotory gap
electrodes are not aligned to Peak. goto step 4.
4. Rotate motor/disc ( depends on your design of motor mount etc) a
few degrees CCW.
5. retest starting at step 3.
depending on how many electrodes you have on the disc, you should only
have to do steps 3,4,5 thru 90 degrees or less of adjustment.
There are other ways to align the motor/disc but it requires a strobe
of some manner that flashes at the same time as the peak of the
voltage running the rotory gap.
Scot D
Stephen J. Hobley wrote:
Hi,
Thanks for all the suggestions. I tried to verify that the motor is true
1800 rpm (30 r.p. 's.' - my fault) by attaching tape to the spark points
and passing the wheel close to a photodetector.
Testing like this I do indeed get 120 "bangs" per second. The phase
varied slightly but in any one second of sampling I saw 120 dips in the
scope. I then put up a trace of the 60 Hz AC to my house and compared
the dips to the peaks and troughs of the AC - by accident my last
adjustment had lined them up pretty well, excluding the odd phase shift
(which I put down more to the "lash-up" I was testing with) all the
"bang" points lined up with just after the peaks and troughs of the AC.
I've just wheeled it outside for another test and this time the results
were even worse than before. As I cranked up the variac I started to get
a burst of sparks of maybe 10 bangs, then nothing, with a total cycle
time of about 1 second. Increasing the voltage evened out the bangs
eventually but the arc length from the toroid was nothing special.
The motor + gap is from Alan -
http://cgi.ebay.com/Tesla-Coil-Synchronous-Rotary-Tungsten-Gap-Motor-Rot
or_W0QQitemZ140255853036QQihZ004QQcategoryZ4665QQtcZphotoQQcmdZViewItem
..so I'm pretty sure it's the right kind of motor.
I would have put this on camera, but the coil does not sound healthy so
I'd rather not run it very much.
Any thoughts?
Steve
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