Winding multilayer coils is a big PITA... / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Winding multilayer coils is a big PITA...

first previous 2 3 4 5 next

Move Thread

LAN_403

jpsmith123

Wed Apr 28 2010, 02:36AM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

Does anyone know what kind of voltage hold-off magnet wire is generally considered good for?

I'm debating making an experimental "pie" type coil by cutting say, 10 radial grooves in a thick-walled polystyrene tube (made from solid rod), and then putting 49 (7x7) turns or so into each groove.

If the core was running at 23 Vpeak per turn, that would result in 322 volts between the first turn of a layer, and the last turn of the overlying layer. It seems to me that magnet wire should be able to handle that, but I'd still like to confirm that or to see some specs or something and I'm having trouble finding any.

Turkey9

Wed Apr 28 2010, 04:59AM

Registered Member #1451 Joined: Wed Apr 23 2008, 03:48AM
Location: Boulder, Co
Posts: 661

I'm not 100% but I believe it's good to at least 600. I heard somewhere that it can stand up to 1000, but it all depends on the type of varnish it has, how many coats, etc.

Patrick

Wed Apr 28 2010, 09:38PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

no need to guess go to wireTron.com to find out, they may give you samples, and they have a program download that will give you exact figures for there wire circ-mils, single, double, triple, and quadurple build, solderable and no-solderable, any color you want.

jpsmith123

Tue Jun 01 2010, 03:42AM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

Well I guess I'm going to try making a sectionalized-winding type of bobbin, out of heavy-wall cpvc tube. I'll probably order the material tomorrow.

I don't like polyethylene, and I've given up on trying to find some suitable and/or affordable pieces of PEEK or polystyrene, so I suppose I'll just have to accept the higher dielectric loss and move on.

In fact I'm still not even sure how lossy cpvc actually is, as I've seen various numbers from about 0.007 to 0.016 (dissipation factor), or something like that.

Picking a number in the middle gives a predicted dielectric loss of somewhere between 1 and 2 watts, depending on other details of design and operation; with most of the loss occuring in the vicinity of the last couple of sections, as expected.

Hopefully two watts concentrated as per the picture won't be too much for the plastic.

IntraWinding

Tue Jun 01 2010, 08:14AM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

How large is that coil?
What's that software?

jpsmith123

Tue Jun 01 2010, 11:24AM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

That bobbin is about 2" OD and about 2.25" long.

The software is CST EM Studio.

Patrick

Wed Jun 02 2010, 12:40AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

in that picture in says "30" for freq, so waht was thisset at 30Hz or 30kHz?

also how can i download that software, i dont see a link to download on their website!

as per your 49 strands, if you mean each of those 49 are tha same strand just looped 49 times per pie, you should be fine, at least for your voltage punch through concern....HOWEVER, i caution youto remember skind depth AND Dpen depth or you will be killed by circulating currents, remmerber higher freq, means smaller diameter, FOR both Pri and Sec. sides.

-Patrick

IntraWinding

Wed Jun 02 2010, 02:06AM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

I'm no expert, but I'd be a bit worried about dissipating a couple of watts inside that plastic. I think it would get quite hot. Would a piece of PTFE off eBay work for you?

Patrick

Wed Jun 02 2010, 02:12AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

if the bobbin is under oil that may not be a problem intrawinding, but he should definatley characterise it, just to be sure.

jpsmith123

Wed Jun 02 2010, 05:22AM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

@ Patrick:

I think that software can be downloaded from a few places on the internet - places that you could find with a search engine; maybe even emule, although I have to add a disclaimer: that would of course not be a legitimate copy.

BTW that S/W is not without its quirks and little problems. It is user friendly in the extreme (maybe a little too user friendly) but it certainly has its limitations: e.g., many times the various solvers (sometimes you have a choice) don't agree with each other to a reasonable degree, IMO; the plots (results) can be artifactual and misleading (especially using the default plot properties) if not downright unphysical looking; many times the automatic/adaptive meshing needs to be manually tweaked, etc.

And yes, that simulation was done at 30 khz (I don't know why it says just "30").

@ Intrawinding:

PTFE would be better than cpvc as far as loss goes, yes, but I was hoping to avoid "slippery" plastics that have bondability problems. And the cost, while much more affordable than peek, is still kind of pricey for the size I would want (2.25" OD round stock).

Anyway, as far as loss in the cpvc goes, after I've refined the model a little bit better, I think the actual number is closer to 1 watt than 2.

first previous 2 3 4 5 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob