[TCML] RE: Need assistance in diagnosing poor performance
Stephen J. Hobley
shobley at userfs.com
Wed Jul 30 08:18:07 MDT 2008
- noted - I'll document the whole assembly tonight and put up a web page so you can take a look.
But in the meantime if there's any general tips that apply to all coils - I would welcome them.
Chris - Great tip about the fluorescent tube BTW - nice way to detect if we are on a harmonic other than the root.
This brings up a great point, and one that has been asked at least once on the tuner design page.
This is the procedure that I use - I leave primary and secondary in place and connect the tuner in between the secondary base and ground. Turning the knob gives me a very definite lowest brightest point on the LED, way brighter than any of the others - I leave the knob set at that position.
Then I remove the secondary coil, short out the spark gap and connect the tuner across the tank cap. I then take my primary tap and move it around the primary coil until I get the dimmest response from the led. This was at turn 11, and not between turns 8-9 as Teslamap said it should be.
At this point I have assumed that the primary is resonating at the same frequency as the secondary. Can someone confirm if this is correct?
Stephen Hobley Photography
317 201 4281
The Laser Harp Project - www.stephenhobley.com/build
From: tesla-bounces at pupman.com on behalf of Lau, Gary
Sent: Wed 7/30/2008 9:30 AM
To: Tesla Coil Mailing List
Subject: [TCML] RE: Need assistance in diagnosing poor performance
We can't give you additional input until you give US additional input. We can't see your coil, remember? ;-) Pictures and specs are needed, particularly of the gap. Yes, 3" is clearly below par.
As stated earlier, the 555 tuner is useful for a rough tuning, but the final tuning must be determined experimentally - i.e. which tap yields the longest sparks.
I'm not sure I follow how you used the tuner. The tuner is used to determine the resonant frequency of the primary and secondary circuits, individually. It's up to you to get them to resonate at the same frequency.
Regards, Gary Lau
> -----Original Message-----
> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On
> Behalf Of Stephen J. Hobley
> Sent: Tuesday, July 29, 2008 7:54 PM
> To: Tesla Coil Mailing List
> Subject: [TCML] Need assistance in diagnosing poor performance
> We're still not getting the performance we would expect out of the Tesla
> coil we built.
> It might have been the humidity that killed it tonight, as performance
> was the worst yet - spark length was only 3" using the safety wand.
> Where should I start in looking for problems? I've built the 555 timer
> based tuner and re-tapped the primary at coil 11, as this gave the
> dimmest indication, as per the instructions.
> Apart from that, I'm a bit stumped.
> I've seen evidence that this coil can give much better performance -
> Alan sent me some recent pictures of a US military coiler over in Iraq,
> getting at least 25" arcs out of his coil - exact same specs.
> Maybe the desert air helps...
> Any help is greatly appreciated.
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