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EDY19

Wed Jul 12 2006, 02:35PM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
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Posts: 408

When winding coils, I put the former in the drill, and once the wire is started, if you make sure there is tension on it and it is only a couple of degrees off perpendicular with the form towards the starting end, the winding is really easy, as the wire just "rolls" or slides down the previous winding right into place. I've never spent more than a half hour on any of my coils- even a 4" by 12 inch wound with 35AWG wire. The biggest thing is making sure that whatever you are spinning the former with is perfectly centered, this helps a LOT! I usually wind my coils at about 180RPM+ once they are started

Tom540

Wed Jul 12 2006, 04:44PM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
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Posts: 617

You guys do guide the wire with your fingers though right? Theres no way I can let it wind and hope it falls into place.

EDY19

Wed Jul 12 2006, 05:12PM

Registered Member #105 Joined: Thu Feb 09 2006, 08:54PM
Location:
Posts: 408

Yes, I hold on to the wire (with higher speed, I use leather gloves) and keep it at a couple degree angle so it "falls" into place. Most secondarys are only a matter of a half hour or less

Jrz126

Thu Jul 13 2006, 04:14AM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

I dont think I can wind mine much faster, that groove is causing problems.

I've been thinking about my overall design and I came up with a pretty good idea, but I just want to make sure its ok.
I have 24 0.56 1000Vdc caps and I'm planning on running 2 paralleled strings in series. It would be so much easier to wire it up like this sketch. The IGBT connects across the 2 circles and that scribble is supposed to be a primary.

Steve Ward

Thu Jul 13 2006, 05:25AM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

That wiring scheme is fine.

Jrz126

Tue Jul 18 2006, 11:57PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Finished winding the secondary on sunday and I'm working on coating it right now. There are a few spots where one of the turns sticks up alittle higher than the others, so I'm probably not going to sand it.

I'm attempting to build a Rogowski coil now and I could use some advice...what size wire should I use? what length should I use for the loop part? etc.

Jrz126

Thu Jul 27 2006, 12:49PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Time for an update and some questions...

I picked up these diodes here:

There was still 4 days left on the auction, but I just emailed the seller and asked if I could purchase them. I paid alittle extra, but atleast I didnt have to wait.
Would they work for my voltage doubler/tripler?

Next, My primary is just about finished, it's not too pretty looking, but I hope it will get the job done. I went with 5 parallel single turns of 1/4" copper. Does this seem reasonable?

The secondary is almost finished, I just have to trim it down alittle bit. Also, how should I seal the ends? I have some 12" MDF circles that fit somewhat snugly inside the cardboard. Should I just put some polyurethane or fiberglass resin over the ends?

I'm going to be putting in some time tonight, and I'll try to get some pictures.

Steve Ward

Thu Jul 27 2006, 06:48PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

First, those diodes are overkill for a multiplier, but they will work very well indeed. They should be heatsinked if running more than 5A or so.

The primary sounds fine, though i have never built an OLTC. Some pictures of the proposed layout would give more information.

I have sealed many coils with either plywood or particle board ends, sealed with polyurethane varnish. It seems to work just fine.

Jrz126

Fri Jul 28 2006, 01:38AM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Here's the pics...
The cap bank and IGBT They;re attached to a doublesided PCB, 12 on each side. (13.44uF) I used some pieces from an old board game as insulators.

A closeup of the insulators.

The rogowski coil...

The primary bolts. I'm going to be attaching ring terminals to these, and then to the top of the double sided pcb.

The spacing of the primary conductors.

the secondary in its final position.

and finally the oscopes...

Purchased from the junk room at work for only $12.00 ($0.25 per pound) The digital scope has a few problems, but its good enough for now.

Jrz126

Sat Aug 05 2006, 09:40PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

I was finally able to get some testing done on the OLTC, I've spent the past couple days repairing my Oscope.
Using a 12V battery charger and chicken stick, I was able to pull a .5" arc off the topload.

How do I calculate the inductance of my primary? I have it wired up as 5 parallel turns.

Oh and is there an easy way to measure the Fres of my secondary?

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