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Re: Rotary Gap Question

Hi Nathan,

At 05:16 PM 12/28/1999 -0800, you wrote:
>Hello to all!
>
>Heres' ANOTHER message from me...
>
>I have a quick question about rotary gaps.  I understand with NSTs it would 
>be greatly to my advantage to have a sync motor running the gap.

A sync motor will fire at exactly the same point on the AC sine wave that
is charging the primary cap.  Thus, your system will fire just when the cap
is fully charged.  A non sync gap will fire randomly during the charging of
the cap and about 1/2 the power will be lost.  Worse yet the neon will see
all kinds of over and under voltages that may kill it (probably not).  The
real danger is if the gap does not fire and the voltage skyrockets past
were the neon or cap will blow up (there was just a song written about this
here on the list ;-))  One thing to always have is a second set of fixed
gaps just across the neon that will fire in case the main gap does not.
These are what we all refer to as safety gaps.  When all else fails, these
simple gaps will fire and protect the neon and caps form over voltage.
Normally they will not do anything.

>
>The motor I have obtained is a turtlish 1000 RPM induction motor.  Is the 
>only difference between sync and induction motors that they have different 
>RPMs? (The sync's RPMs being a muliple of 60)

Assuming you have 60Hz AC where you live.  You will want a 1725 RPM motor
of about 1/4 horsepower.  These can be converted to 1800.00 RPM with some
work.  I don't think your 1000 RPM motor can be converted.  See the follow
pages for motor conversion info and a bunch of pictures of my sync gap.

http://www.peakpeak-dot-com/~terryf/tesla/misc/syncmot.zip

http://www.peakpeak-dot-com/~terryf/tesla/misc/RGAP.ZIP

http://www.peakpeak-dot-com/~terryf/tesla/experiments/modact/modact.html

>
>If that were true, then couldn't I put a high quality speed control on the 
>motor, run it at 900 RPM with 8 gaps, 120 breaks per second, and ride the 
>sin waves like a surfer?

Trust me, you won't be able to do it well enough.  You will also have other
things on your mind and messing with the gap trying to chase the AC wave
will not be worth it.  There really are motor controllers that would do it
(exact RPM plus phase control) but they far are too elaborate for our use.
They are also highly electronic and may just get fried if (when) something
arcs.  Getting a regular motor and modifying it is the best way to go.
Many people have thought of all kinds of other wonderful ways but about
100% of the sync gaps use modified motors.  Hint, hint ;-)

>
>Or has my train of thought wandered too far, and assumed too much?

Nope!  your right on track asking all the right questions.

Cheers,

	Terry


>
>Thanks,
>Nathan
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