Sync motor modification

From:  D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent:  Wednesday, January 28, 1998 12:03 PM
To:  Tesla List
Subject:  Re: Sync motor modification

to: Gary

If you are starting with only 1/8th HP motor and then grind the 4 flats you
might not have enough power to run the RSG.  If you are thinking of another
motor in the future we have some nice already synchro 1800 RPM units for
$30 apiece.  You dont have to modify them and they run excellent with a 7
inch rotor and 4 electrodes.  


> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: Sync motor modification
> Date: Wednesday, January 28, 1998 7:10 AM
> ----------
> From:  Gary Lau  28-Jan-1998 0803 [SMTP:lau-at-hdecad.ENET.dec-dot-com]
> Sent:  Wednesday, January 28, 1998 7:36 AM
> To:  tesla-at-pupman-dot-com
> Subject:  Sync motor modification
> >> I have both acheived good outputs from neon systems using sync gaps,
> >> without any tranny failures, but only time will tell how effectively
the sync
> >> gaps "protect" the trannies.  Perhaps if more folks start using sync
> >> on their neon systems, a long term consensus (on tranny longevity) 
> >> will emerge. 
> >Funny you should mention that.. I am in the process of seeking out 
> >the directions to modify a motor to sync operation for just that reason.
> >[More power for less..] I figure if I smoke the tranny now, well, it
> >gave me a good result, and I can't really learn too much more from it.
> I'm just about ready to test out my sync RSG with a 15KV/60mA NST.  For a
> motor, I bought a 1/8 HP 1725 RPM motor for $4.95 from H&R Surplus.  This
> unit has a 3.5" dia rotor.  I milled four flats onto it, each being
> 1.00".  While the flats should have been 1.30" to each cover 1/8 of the
> circumference, I thought it safer to remove less and see if it works.  It
> sync's right up so I'll stick with the 1" flats.  Only problem is, there
> are four angular positions, each 90 deg apart, from which the motor will
> stall if started there.  Perhaps if the RSG works out well, I'll buy
> another motor and remove more material and see if that resolves the
> stalling.
> A question on adjusting the phase of a sync RSG.  It would be best if I
> could do this without attempting the subjective test of when I have the
> longest spark, turning off power each time.  I did a dry run last night
> without my secondary installed, and as I rotated the motor case, saw a
> clear point of maximum gap arcing.  Is this a valid indicator of the
> correct rotor phase for when the TC is completely assembled?
> Gary Lau
> Waltham, MA USA