Tesla Forums

Hi,
My name is Tony and I'm writing from Alberta, Canada. 

For the past few weeks I've been working with my first coil which has a static spark gap.
I would now like to look at evolving up to a rotary spark gap design.  Other than EBay, can anyone
recommend a spot where I may be able to purchase a 3600 rpm teletype motor??

OR
are there pre-built rotary spark gaps available?? 

Thanks for your help.
Tony

I'm not a SGTC guy but from what I know, all it has to be is some sort of synchronous motor. You can find these in microwaves and also at surplus stores.

Maybe some one more in spark gap coils can be of some more help.

Eric 

Actually, it does not HAVE to be a synchronous motor.  There are 2 type of rotary gaps you can build, synchronous (SRSG) and asynchronous (ARSG).  I could try to explain the differences here, but nobody does a better job of explaining the differences providing simple plans then Terry Blake.  Check out the link below:

http://www.tb3.com/tesla/sparkgaps/

Just note: You do NOT want to use an Asych gap with NSTs.  They put too much stress on the transformer.   ASRGs work really well with lots of power such a MOT Stack supplies supplies and pole pigs.  Synch gaps tend to put out the largest streamers.

As for syncronous motors, you can't beat this price on ebay. 

http://cgi.ebay.com/NEW-Oriental-Motor-Synchronous-Motor-3SK10GN-AUL-/220725242672?pt=LH_DefaultDomain_0&hash=item33643feb30#ht_653wt_905

I bought one myself for my next SRSG.  It's 1800 RPM, so you will need to use 4 break points rather than 2.  Check out Blake's site for a super-simple propeller style SRSG.

Hi,
Thanks very much for all of your comments, I appreciate the help.

I picked up a Teletype motor this afternoon from a friend who has a huge selection of used
electrical equipment and it was free of charge!!  We tested it and it appears to be working well.

I've also visited Blake's site and I would like to build one of his propeller style SRSG units.  Seems fairly
simple and highly effective.
What diameter of tungsten electrode would you recommend??  1/16" or smaller??

Please take a look at the photo of the t.type motor I picked up (not sure where photos are attached on these messages).

Here's a video of my first coil, I was doing a morning of demos at my school:
http://www.youtube.com/watch?v=fHyLKdueHME
.
I would prefer to maintain most of this coil and adapt a SRSG to it.  At the conclusion of the morning the coil
"died" and the safety gap continued to fire and nothing else happened!!  I tested the NST and it seems to be fine, do you
think the mmc is fried??

Thanks for your help.
TR.

Great job on your first coil! 

Looking at the video, I noticed a number of streamers coming off the toroid at the same time.  You could probably reduce the number of simultaneous streamers and increase the streamer size by simply increasing the size of your toroid. 

Do you know if that motor is a synchronous motor?  It will have to be synchronous to build an SRSG.  If you are unsure, you could use Terry's process for verifying that a motor is synchronous.  See Link:

http://www.tb3.com/tesla/sparkgaps/sync/index.html

As for the Tungsten Electrodes, I would not use smaller that 1/8. The larger the electrode, the more power you will be able to send through it.

What are the specs on the TC?  Power Supply?  MMC?  What caps are you using in the MMC?  Are you using an NST filter?   I will need to know some more to help figure out why it might not be working anymore.