Re: Synchronous rotary gaps.
Sent: Saturday, September 13, 1997 6:59 AM
Subject: Re: Synchronous rotary gaps.
On Fri, 12 Sep 1997 23:57:12 -0500 Tesla List <tesla-at-pupman-dot-com> writes:
>From: William Noble[SMTP:William_B_Noble-at-classic.msn-dot-com]
>Sent: Friday, September 12, 1997 2:04 PM
>To: Tesla List
>Subject: RE: Synchronous rotary gaps.
>aren't the motors used on the old disk drives (the ones driven by AC)
>synchronous?? and also old phonograph motors (remember phonographs -
>things that turned at 78RPM??) - I suppose I can test this with a
>or something if I really want to.
Yes there are small sync. motors out there. When I stated that
fractional H.P motors were hard to find I meant small motors which had
enough power to run a rotary disk with electrodes. The small motors
found in phonographs (some cheapies use shaded pole non-sync motors) and
reel to reel tape decks are very low in power and have gear reduction to
increase torque. If they were used to direct drive a rotary disk at
1800 or 3600 R.P.M. I feel there would not be enough torque available.
As for computer disk drives I did not think about them being synchronous,
maybe one of the old 8" drive motors might work, however once you start
loading electrodes on a disk, the added weight and air resistance take a
toll on small motors.
>Sent: Thursday, September 11, 1997 9:11 PM
>Subject: Re: Synchronous rotary gaps.
>On Wed, 10 Sep 1997 22:30:19 -0500 Tesla List <tesla-at-pupman-dot-com>
>>From: Dale F. Pfaffle[SMTP:pfaffle-at-tele-net-dot-net]
>>Sent: Wednesday, September 10, 1997 8:40 PM
>>To: tesla list
>>Subject: Synchronous rotary gaps.
>>These synchronous rotary gaps, I am assuming (and I know what that
>>are done with sync. motors. Is this something coilers are buying or
>>that are being modified?
>Sync. motors in the fractional H.P. range are very rare, even in the
>integral H.P. range. Most sync. motors in use for rotary spark gaps
>custom made, either by the coiler or a machine shop. You can modify
>induction motor to run sync. by milling, filing or grinding flats on
>armature. An example is given by John Freau on one of Richard Hull's
>(TCBOR) video tapes that he sells somewhere in web land. I believe it
>I also sell modified sync. motors which are approx. 1/25 H.P. 3600
>R.P.M. have ball bearings with a 5/16" x 1" shaft. I have been
>them for $22.00 plus shipping.
>This motor on my prototype will spin a 7" dia. phenolic disk 1/4"
>with 2-electrodes running 120 breaks per second with power to spare.
>If you are interested in one, e-mail me at:
> teslaman-at-aol-dot-com or teslaman-at-juno-dot-com