Re: On the fly tuning of a TC

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Harrison by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mike-at-whitewing.co.uk>

You should be able to control a stepper moter easily (and more
safely!) with a DC supply and a rotary switch to rotate the power
between the phases. Get a switch which has no endstop (or remove the
stop) , and operate it via a long plastic rod for safety. 

On Mon, 16 Apr 2001 08:03:00 -0600, you wrote:

>Original poster: "Jason Petrou by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <jasonp-at-btinternet-dot-com>
>
>Hi all,
> 
>I was tuning my 360W coil yesterday and it took me about two hours - I was
>finding it very hard to zero in on the exact point on the primary tap.
> 
>I recently worked out how to control a 12V printer stepper motor using the
>RS232 port of my computer (serial). The motor had been salvaged from an old
>epson laser printer, and worked in one degree increments - almost perfect for
>tuning an SG.
> 
>Anyway I bought some serial cable (the type that is usually used for direct
>cable networking) and cut off one of the ends, and connected it up to the
>motor, (and plugged it in to a 12V tranny etc) and connected it to the bottom
>of my TC. I fixed a perspex arm onto the shaft and one to the my fuse holder,
>then used two U shaped pieces of perspex top hold them in such a way that the
>holder assembly could slide up and down the arm, but not to the side, rather
>like a piston and crankshaft mechanism.
> 
>I screwed the motor underneath my TC's primary winding, with an 18mm piece of
>acrylic as an insulator, and connected the arm assembly. with the power to the
>TC off i tested it and although it was a little jerky the holder could slide
>from the 4th to the 12th wnding - enough movement for me. I pluged the cable
>into the computer and run the basic written pulse program.
> 
>I turned my NST on and amid a shower of sparks from the primary started to
move
>the holder. suddenly a streamer hit the primary (something very rare - i use a
>double toroid configuration) and the computer turned off. It turns out that I
>had fried the mainboard of the PC (it was a crappy old 486 not worth the £10 I
>paid for it) thorugh toe primary cable
> 
>I have still not learnt from my mistakes, and am trying to develop an new trpe
>of on the fly tuning. Please reply wiht ideas (or just to take the piss!!!)
> 
>Thanks all
> 
>Jason
>
>
>