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Secondary Problems Need Help

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LAN_403

Coronafix

Fri Aug 21 2009, 07:12AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Myke wrote ...

As said before though, racing sparks usually appear near the tops of secondaries and not near the bottom.

In my experience they occur all the way up the secondary but mostly at the bottom.

Have you tuned it yet?

hvguy

Fri Aug 21 2009, 07:33AM

Registered Member #289 Joined: Mon Mar 06 2006, 10:45AM
Location: Conroe, TX
Posts: 154

Jonathan, you secondary is hosed. Something no one else has pointed out about the video is the very severe turn-to-turn arcing. This means your secondary wire insulation has either broken down between turns (possibly due to racing arcs) or it was damaged before you wound it. Either way you now have arcing occurring underneath your poly, between individual windings. This is not repairable, at least not with out removing the windings.

What likely got you here? Some combination of poor tuning, too high coupling, and racing sparks or a primary flash over. Could have been cheap wire too.

Jonathan Dennis

Fri Aug 21 2009, 03:32PM

Registered Member #2153 Joined: Wed Jun 03 2009, 03:19PM
Location:
Posts: 69

MODERATOR - FIXED DOUBLE POST

So if It's properly grounded, could that stop the turn to turn arcing?

So in other words my whole project has been screwed by my secondary and I need to buy new magnet wire and start all over? I am going to try complaining about the poorly spooled wire, the original kinks and nicks in the spool are probably the source of these problems because I was very careful when winding by hand. Can I make use of the "useless" secondary wire, I hate to take it and scrap it for a few bucks.

*Sorry for double posting I hit the back button to change something and it posted twice. *

Herr Zapp

Fri Aug 21 2009, 11:37PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

JD -

It seems like we're going over the same stuff over and over again, so here's a quick summary:

1. Your secondary MUST be wound with magnet wire that has no nicks or bare spots in the insulation, and no overlapped turns;
2. Your secondary MUST be electrically connected to a good, low-impedance earth ground;
3. Your secondary MUST be electrically connected to your topload;
4. Your primary and secondary circuits MUST be "tuned" so they resonate at the same frequency;
5. Your primary-secondary coupling factor MUST fall within a specific range of values (typically 0.1 to 0.16).

If your coil doesn't meet the above criteria, it won't work. PERIOD.

If your secondary was wound with wire that had damaged insulation, it is probably beyond salvage. The arcing shown in your video clip seems to show that there are scores of spots with damaged insulation. Just accept that as fact, throw the damn thing away, and try again. Wind a new secondary with high quality, double-build insulation magnet wire, make sure that your coil meets criteria #1 through #4, and try powering it up again.

(Incidentally, do you have a variac to allow you gradually increase input power, or are you hitting your NST with instantaneous full line voltage?)

Send me the old secondary, and I'll perform a definitive failure analysis to confirm EXACTLY what was wrong with it.

Regards,
Herr Zapp

teravolt

Sat Aug 22 2009, 07:42PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

I noticed that you coating on the secondary has a wood stain in it and if it conducts your secondary is toast. Next time use a clear eurethane. Also you tesla is clearly out of tune try adding some capacitance to your primary ciruit and give us some pictures of the primary circuit to see what you have done

Jonathan Dennis

Sat Aug 22 2009, 09:59PM

Registered Member #2153 Joined: Wed Jun 03 2009, 03:19PM
Location:
Posts: 69

It was not working even b4 I put the "stain" on. It's not stain though, it's polyurethane stain mix. Where would you recommend I get my wire, I will buy it from a tried and tested source this time. I contacted the original source of my wire and sent a complaint about the poorly spooled wire, hopefully they will send me a new one free of charge, but ... I'm a bit doubtful. What do you mean by "add some capacitance" to your primary? Are you just referring to the tuning process? I started at turn 3 and little by little worked my way out. I found that I got sparks highest up on my secondary when tapped at turn 5. This makes little sense, because WinTesla calculated I would tap at turn 8-9.

Jonathan

Herr Zapp

Sat Aug 22 2009, 11:27PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

JD -

Let's keep it real simple ........ have you figured out yet WHY you don't have continuity from your ground rod to your topload???????

Regards,
Herr Zapp

Jonathan Dennis

Sun Aug 23 2009, 12:01AM

Registered Member #2153 Joined: Wed Jun 03 2009, 03:19PM
Location:
Posts: 69

I don't know for sure. But my best guess is the resistance of the 28 gauge wire is 1700 feet of tiny wire. I did get (from topload to base of secondary) a reading (don't know what the reading was) of .046 on my voltmeter, I think that was with it on the 200ma setting.

Herr Zapp

Sun Aug 23 2009, 12:23AM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

JD -

You really, REALLY need to get some entry-level understanding of basic electronics before proceeding. If you don't know that you need to use the RESISTANCE measuring function of your multimeter to measure resistance (and not a CURRENT measuring function), then you are in over your head.

I gave you very specific instructions on how to calculate the DC resistance of your secondary. One quick and easy check of your secondary would be to see how close the MEASURED resistance is, compared to the CALCULATED resistance. This will detect simple problems like a broken wire.

Since it appears that the coil you actually built differs significantly from the design specifications you posted back on June 4, it might be worthwhile to post ALL the design specifications for the coil as you actually built it, as it stands today. Something might become obvious that is contributing to your secondary flashover problems.

Regards,
Herr Zapp

Jonathan Dennis

Sun Aug 23 2009, 02:30AM

Registered Member #2153 Joined: Wed Jun 03 2009, 03:19PM
Location:
Posts: 69

I understood your directions for calculating the actual resistance and comparing it with the calculated resistance, but I am at college now, so it will be several weeks b4 I can get around to it. I'll probably open a new thread about it when I go back home to visit. Thanks for your help so far. By the way, I am over my head, but I like to dive right into things, I learn best by trying and failing that reading theory. Just so you know I have read the theory, like crazy but some things just take experience and time. I'll try to get updated specs online soon.

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