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how well does a secondary need to be wound

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teslacoolguy

Tue Feb 26 2008, 05:50AM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

I just got finished windinga good sized secondary around 6" pvc pipe and some of the windings are a little loose and sticking up a little but they are not overlapped and i was wondering if that is ok or do i need to tighten them a little?

Andyman

Tue Feb 26 2008, 06:45AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

If you can, tighten them up. Loose windings that stick out are just asking for corona or to be arced to.

uzzors2k

Tue Feb 26 2008, 04:24PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

If some of the overlapping windings have a large enough voltage difference they will arc to each-other. I've had this happen and they nearly burned apart, ruining the secondary.

teslacoolguy

Tue Feb 26 2008, 06:09PM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

well according to my calculations 1200 turns at .5megavolt output there is approxamately 400v between each turn but im not going to take any chances and im going to smooth everything out

HV Enthusiast

Tue Feb 26 2008, 08:59PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

teslacoolguy wrote ...

well according to my calculations 1200 turns at .5megavolt output there is approxamately 400v between each turn but im not going to take any chances and im going to smooth everything out

For a small-med sized coil, 500kV is much much too high. Even very large coils would have difficulty getting that high.
Remember, arc length alone isn't enough to use for measuring voltage level. The excessive arc length you see is due to arcs following
previous ionized air channels which makes low voltage output reach excessively long arcs.
Even single shot discharges are not representative of actual voltage output as they are AC and even a single pulsewidth output will basically act like an arc propogating several times through
the same ionized air channel.

For a small-mid coil, you're looking at around 50kV to 100kV output.

If you do want to go on arc length alone, you need make a single shot output, but limit pulsewidth for only ONE cycle of AC. This will give you a much more accurate representation of output voltage.

teslacoolguy

Tue Feb 26 2008, 09:19PM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

no it is a very large coil based of

and i will be using almost identical components that he used and here is a pic of the secondary

Ultra7

Tue Feb 26 2008, 09:35PM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

I like winding my own coils, call me crazy, but I do.
My winding Jig is primitive, with just a cordless drill to do my turning.
With any of the thousand things that can go wrong while winding a coil, mine do not come out perfect. Mind you I have no overlapping turns, but sometimes I get little gaps in between the windings.

Rather than rewind the whole thing because of 3 or 4 little gaps, I just keep going.

I have yet to have any catastrophic failures with the finished product.
Because I'm not really trying to create a "Museum Piece", I can live with tiny imperfections.

What can go wrong while winding?

1. The magnet wire wraps itself around the threaded support rod, causing the whole thing to crash to the floor.
2. Taking a break while winding, you light a smoke and then continue winding. After 3 seconds, the wind changes and the smoke gets in your eyes.
3. The kids spill your beer.
4. The whole thing comes undone because the tape you are using sucks.
5. your Girlfriend needs you to change the clothes from the washer to the drier, and when you come back, the kids have decided to "Help" you wind the coil.
6. the spool of wire has a kink exactly in the middle of the coil.
7. While coating the secondary, the kids decide to help you by turning on the leaf blower.
8. The drill somehow magically gets put on high speed while you were at the store replacing the spilled beer.
9. You run short of magnet wire. . .
10. the winding jig breaks
11. after winding the coil, and letting it dry in a nice safe place, you discover that a mosquito has invited its entire clan to roost on the slowly drying coil.

Anyone have any other mishaps?

teslacoolguy

Tue Feb 26 2008, 09:51PM

Registered Member #1107 Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792

lol i have one more for you and this has really happened to me

go on a vacation for 2 weeks and when my mom turns the heating all the way down and the pvc form shrinks a little overlapping all the windings and coming home to a catastrophic mess and that is exactly what happened

and for the record i wound that by hand because my winding jig is not finished yet and luckily i dont have any little brothers or sisters

FireBird

Wed Feb 27 2008, 12:50AM

Registered Member #1104 Joined: Tue Nov 06 2007, 07:38PM
Location: Wisconsin, United States
Posts: 34

Yea, I also wound my coil by hand and it took me a while to do it. It annoyed me a lot though because half-way though the winding process I discover that somehow my wire has formed a kink while coming off the spool. Fortunately it isn't that bad but itâ€™s still noticeable. Thankfully it hasnâ€™t caused me any problems but just to be on the safe side you should probably tighten up your windings.

Hazmatt_(The Underdog)

Wed Feb 27 2008, 02:53AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Don't you just hate it when the temprature changes, HEHEHEH. I just got done tightening up mine because it got cold here so I feel your pain.

I wouldn't worry about your coil too much because its a beautiful coil, you did a good job. The only thing I would suggest is don't feed the wire internally like that because you do on occasion get arcs running down the inside, and that's not good.

I wind my coils with threaded rod and a drill too. I've had the chuck fall off, rod get loose and the jig just keeps goin' (not good), and I've gotten a bit of my hair caught in there too (28" long).

I prefer the cheapo-drill jig because I can set it up in 15 minutes, that and I don't have a lathe.

I would definately wind in cooler tempratures though, that way when it warms up you don't have as much of a problem.

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