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Check design of first spark gap coil?

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ScotchTapeLord

Mon Jan 03 2011, 12:31AM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
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Posts: 635

The price is a little higher for heavy gauge, which you have to call them up to order. They were pleasant to deal with, in my opinion.

Herr Zapp

Mon Jan 03 2011, 04:03AM

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

Bear in mind that Parawire sells a lot of magnet wire on eBay that they identify as "hobby wire" for use in non-electrical applications (floral arrangements, etc.).

Before ordering, I'd get something in writing from them that clearly states that what you are buying is first quality magnet wire, and not "hobby wire".

Also, the "Magnets4less" site seems to list both virgin Essex magnet wire (Essex being a well-known US producer of high-quality wire), and "no-name" magnet wire.

Let the buyer beware .....

Herr Zapp

Gunboat

Mon Jan 03 2011, 01:42PM

Registered Member #338 Joined: Thu Mar 23 2006, 12:28PM
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Posts: 41

Hey! I found some magnet wire at a local industrial motor place.And they were cheap.You should be able to find a place like that where you are located at.As for caps,I do believe that Eastern volt has the best prices,at least that's what I have seen.

Gunboat

Mon Jan 03 2011, 01:44PM

Registered Member #338 Joined: Thu Mar 23 2006, 12:28PM
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Posts: 41

Oh yeah,one other thing,I went to the local flea market and bought a angle grinder,30 bux I think.Made a rotary spark gap with it.

ScotchTapeLord

Mon Jan 03 2011, 04:11PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
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Posts: 635

Herr Zapp wrote ...

Bear in mind that Parawire sells a lot of magnet wire on eBay that they identify as "hobby wire" for use in non-electrical applications (floral arrangements, etc.).

Before ordering, I'd get something in writing from them that clearly states that what you are buying is first quality magnet wire, and not "hobby wire".

Also, the "Magnets4less" site seems to list both virgin Essex magnet wire (Essex being a well-known US producer of high-quality wire), and "no-name" magnet wire.

Let the buyer beware .....

Herr Zapp

The wire I received from Magnet4less was advertised as Essex magnet wire... but I'm thinking that was BS.

Parawire offers double and heavy build, not sure why non-electrical applications would need extra insulation. It's possible they just put the rejected stuff they can't sell on their site on ebay, as they do not label the stuff on their site as "hobby wire."

Steve Conner

Mon Jan 03 2011, 04:58PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Herr Zapp wrote ...

That's a beautifully constructed MMC, Herr Zapp! Is it one of your own? I think those yellow RS brand caps are made in England, it's unusual to see them in an American build.

In my experience, a Tesla coil is quite forgiving of dodgy insulation on magnet wire. I've got a couple of coils with overlapping turns, even sections burnt out by flashovers and repaired crudely (one even with PVC insulated hookup wire instead of magnet wire) and they're still sparking. But I guess it's still a good idea to get good quality wire in the first place. I got my last big spool from a wire merchant who resold to motor rewinding shops.

I think Steve Ward made some coils with the green magnet wire from Parawire. They have two separate online stores for "craft wire" and "magnet wire", so I guess they are aware of the difference.

Herr Zapp

Tue Jan 04 2011, 12:36AM

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

Steve -

Ja, es ist mein!

Actually, this MMC consists of 4 strings of caps, two on each side of the board. The "turret standoffs" on opposite sides of the board are connected by short pieces of threaded nylon rod, so both standoffs use a common mounting hole. These are .047uF Arcotronics caps from the UK; capacitance of the array is .014uF, "DC" voltage rating is 21KV.

Below that is a much older MMC I assembled in the same way, but using GE 42L series caps (.1uF @ 3KV). Capacitance is .033uF, "DC" voltage rating is 36KV. Although this MMC has never experienced insulation breakdown operating from a 15KV, 120ma NST bank, I now think the caps and resistors are far too close together. One of these days I'll rebuild this MMC on a larger baseboard.

Both these MMCs were built using standard .5W carbon-composition resistors, before I discovered the Phillips/Vishay/BC Components VR-37 series with their 3.5KV rating.

Herr Zapp

dithersail

Wed Jan 05 2011, 06:10PM

Registered Member #3515 Joined: Wed Dec 15 2010, 03:05AM
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Posts: 11

Agreed Mr. Zapp, beautiful work - Also thanks for comments on wire. Zeroing in on what I need to have a good first coil and have it be a fun experience - and not destroy some fairly pricey stuff. Please keep commenting....

HV Enthusiast

Thu Jan 06 2011, 01:51PM

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

That indeed is beautiful work Herr Zapp. Thanks for sharing your photos!

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