Re: [TCML] Coil Volume and Others

[Joe Mastroianni <joe@xxxxxxxxxxxxxx>]

Ok, so I got caught in a confluence of many parameters - 
twice I had the coil working well.  Not flawlessly, but well.   Still some primary arcing at nearly 100% power.   Turns out the arcing is less of a problem when everything is timed and tuned well.

Ah...but then, one can't leave well enough alone.  

Tweaking the timing knocks the primary tuning off, which you find out by suddenly seeing racing arcs on the secondary where before there were none.  Tuning is also very touchy.  Usually I can be off by more than two full turns before I see racing arcs.  This was more difficult.

Of course, live with racing arcs more than you should, you get burn marks, and then eventually your secondary burns through...

I want to say that the idea of stacking toroids to increase the topload did seem to work.  But honestly, I can't tell if it was that or adjusting the gaps on the SRSG - which had more of a positive effect in terms of reduction in racing arcs on the secondary and the primary-between-turns-arcs.  

Oddly, I checked and rechecked my JavaTC numbers, and it kept giving me answers that did not correlate to what I was seeing.  So clearly, my setup is in some state of error, because JavaTC works, as I have previously proven.  I think it's time to jettison this SRSG, as much as I enjoyed building it.  AT the  minimum, the propeller was much easier to tweak - though also needed all sorts of twiddling to get it dialed in.  

As I have burned up one secondary, I do have one left though it was designed for lower power, where it worked swimmingly.  I will commence winding a new secondary, and at the same time try an ARSG with a lower power setup just to see what will happen.  From Amazon I've secured & mounted one of those blower motors that Terry Blake suggests on his website.  It's mounted into the same frame as the propeller gap, which I had previously set to 240bps.   So there are 4 presentations per revolution, identically to what Terry has on his website.  And this motor will run at 19,500 RPM with 120V, so the BPS should be adjustable to a pretty high, and hopefully safe range.  But I do have to configure some means to protect the world at large from the thing.  The idea of that tungsten rod flying out of there at some bullet-like speed does really bother me, which is one reason I liked the G10 disk better.  But it's easy enough to configure a polycarbonate shield.

So I will experiment with that tomorrow with my lower power secondary in parallel with genning up some sort of winding jig.

If I burn that up I will go to the new secondary and the propeller gap in SRSG mode.

There are many times in the past week or two I wish I had taken up something easier and less painful,  bungee jumping or building rocket engines.

Joe


On Jul 30, 2010, at 4:40 PM, Gary Lau wrote:

> It makes sense that the safety gaps are more prone to firing at 120 than
> 240BPS.  Assuming you're using the same cap size, the cap has only half as
> long to charge at 240BPS, so it won't get to as high a voltage.
> 
> I know what "TDC" stands for, but I'm not sure it has any useful meaning
> relative to sync gaps.  You're not thinking that the rotational point when
> mains voltage peaks is where the sweet spot should be, are you?  The correct
> timing can only be determined experimentally, and will differ depending on
> cap size and Variac setting.  Setting a sync gap phase incorrectly can
> definitely result in safety gap firing.  As I recall you're still using a
> relatively small-value cap in your Freau phase adjuster.  I strongly
> recommend using something larger to allow you greater latitude in adjusting
> the phase.
> 
> Regards, Gary Lau
> MA, USA
> 
> On Fri, Jul 30, 2010 at 6:31 PM, Joe Mastroianni <joe@xxxxxxxxxxxxxx> wrote:
> 
>> Well, I tried 1.5 turns and that was a non-starter (literally).
>> It's more like 9 turns of 1/4" refrigeration tubing, 1/4" apart,  to tune
>> with 41nf, 22" of 26Ga wire on the secondary, etc.  At least, that's my
>> empirical result.  Lemme try doubling up on the toploads.  I've got another
>> (smaller) toroid.  I will try stacking.
>> 
>> But I'm finding out  a lot of interesting stuff.  Like:
>> 
>> - My Terry Filter safety gaps fire when I have the SRSG set at 120bps and
>> it's out of tune.    It does not fire when I have the SRSG set to 240bps and
>> it's out of tune.
>> - I get arcing on the primary when I run at 240bps and the primary is in
>> tune, but the SRSG is off TDC
>> - I do not get arcing on the primary when I run at 120bps and the primary
>> is in tune but the SRSG is off TDC (maybe this is because the terry filter
>> gap is firing)
>> 
>> 
>> Because I have a persistent and driving need to construct things, I'm
>> turning my propeller gap into an ARSG as I write this....  I suppose if I
>> blow up my NSTs I'll just go build a DRSSTC.  I have one of Dan's kits
>> sitting in the box in the corner, calling my name.
>> 
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