Transformer insulateing tape?

On a sunny day (Sun, 20 Jun 2010 11:19:26 -0400) it happened Hammy wrote in :

Sorry, I did see a whole lot of 'I AM PROTEUS' replies and could not resist. To stay on the (original) subject, I remember one word from my transformer factory days: Melinex.

That said, I have wound a TV hor output transformer with normal A4 paper as isolation. As long as temperature stays low, and it does not get wet, it works. I am not sure if you can get Melinex in low quantities.

You can find stuff like this at an industrial liquidator shop, if there is such an animal as that in your town. In this area, there are several. Suprizingly, old mil surplus shops can also have raw goods.

The specific tape that I was talking about is a 1 mil thick film with a 1.5 mil layer of adhesive, as specified in the data sheet for which I gave the URL (which you have snipped).

Since the data sheet also lists a thicker variant of the same tape, you aren't telling me anything I didn't know. Since the OP was asking for material that he could buy off the shelf and in small quantities, the availability of thicker and thinner tapes that you can only order in volume from specialised distributoers who mostly don't hold stock isn't of that much relevance to this thread.

But where can we get it? Off the shelf and in small quantities?

t

Sure.

-- Bill Sloman, Nijmegen

And why is it you wish to split the primary winding and place half UNDER the secondary, and half OVER the secondary?

Kapton is only feasible on larger form factors. If this is a small pot core it will not be as easy to use kapton, and Kapton does not"sink in" it stays flat, which defeats your original suggestion that they be nested as tightly together as they can.

The poly tape has just as good electrical resistance, and takes up far less bobbin space. The stuff is just too inflexible for smaller applications. I have used it on say a 1.5" dia pot core, but it only had a few primary turns and they were inside a Teflon tube already and wound flat, so the Kapton fell on top of it flat. I doubt he will get the same winding profile with 3 x #30.

Not to mention the way the industry does it in nearly every case.

If the step up is not that much, he is sure to be OK with cheap xformer tape too.

He mentioned 12V and 5V, so I do not think he is doing an HV application, and he could probably get away with zero transformer tape using simple double strength mag wire. Granted I would still separate primary from secondary, but I doubt he needs to worry about creepage distances in such a LV application. He is already isolated from the AC line.

If there is bobbin space, I would do things like switching to say 3 x #28 if it fits. Or two flat wound.

He gave a lot of info, but there were still a couple details to talk about.

You're an idiot. One of these days, you are going to stick your neck so far out, and your foot so far up your pathetic ass, that google will finally figure out that you need to be removed, and perhaps even hit you with some nice, on-the-books NYPD charges. So, you had better watch your ass, troll.

He is too retarded to turn off the caps lock key.

Do you actually believe that he ever had the brains that real Mac users have? No, this putz bought one because he lost his WebTARDTV account due to excessive abuse. He is so mad at all of us that complained about his dumb ass, that he incessantly trolls, abuses, and annoys the group. Cross-posting by other idiots has allowed his disease to now spread to other groups that the little retard was previously unaware of. Thanks, dumbfuck cross-posting idiots.

SLowman, stupid as ever. The 'mil' is a quite standard unit of measure, and yes, it's used by woodworkers, too.

"bizarre"? You're nuts (he is). Two are simple order of magnitude values, and one is one half (nothing bizarre about that fraction) of the order of magnitude above it.

Yeah. Sloman fits OUR definition of it.

Mostly for sealing up cable ends. Not so much for attaining reliable electrical isolation. Likely depends on the tape, the maker, and the way it is made. I have seen it actually be an impregnated fabric type tape.

I can *merely look* at a gap or the width of a solid, and guess the gap pretty close under an inch, and even fairly close up to about 8 inches. I even guess larger spans pretty well, but the resolve switches to whole inches.

I can *see* nearly the entire range under 50 mils though. I get DAMN CLOSE nearly every time.

Only AFTER one familiarizes the observer with the standards.

1mm 1cm 1Dm etc. Numbers below 1mm get easier too.

No different than thousandth inch numbers under say 0.1"

No....

Interleaving windings is a pretty common technique to reduce leakage inductance and improve coupling there is a tradeoff it increases interwinding capacitance.

The front end is protected with two MOVS 395V max clamping 25mm types one right after the NTC and before the CMC and one right before the

600V bridge 495 max clamping. The line filter is a 2x 27mH 1.7Arms CMC two 0.47nf X2 caps LN and two 2.2nf Y2 caps LG and NG.

As I said earlier its not being tested for regulatory requirments. I just put a beefy line filter on there because I dont want it interfering with My DSO and anything else I'm useing.

I don't have test equipment to thoroughly test the line filters effectiveness but it is better then most of the crap I've taken apart. Between the line filter attenuating fast transients and the 270uf bulk cap and MOV it should be well protected short of near lighting strike.

The outputs are protected from OVP from sensing the AUX winding the controller will be latched off.

A similar method is used for sensing a short the AUX would collapse under a short the controller NCP1203 will enter burst mode trying to restart.With a small inductance you can get a current build up in the primary under a short due to no counter EMF to ramp down the current well other then the VF of the output rectifiers so it would have to be tested of course. I think it should be good though. It worked in other flybacks using NCP12XX controllers but the primary inductances was higher.

Insulation from primary to secondary is all that's necessary.

I'm limited by what's available I have 22AWG, 26AWG and 30AWG. I've mainly used the 26AWG. I think once you get larger then 26AWG skin effect becomes a problem. Mind you I have coil craft flyback transformers with what looks like at least Parallel 21AWG secondaries.

I can and have gotten heavier gauge magnet wire from some rewind shops in town and actually I'll check if he's got the tape on Monday.

I know sometimes the temptation can be too much.;-)

isolation.

I'm going to check a couple of motor rewind shops in town see if they have the tape But thanks for the suggestion.

88 is not recommended if you're after safety. It cold flows and may cut through, especially if things warm up. Windings produce lots of pressure on the tape.

Look on eBay, you can find people selling transformer tape for cheap.

--
Mark

Except that *I* said THINNER, idiot.

Are you dyslexic?

Except that single rolls ARE available for purchase, idiot.

Jeez. Is that an acknowledgement or insult? If the latter, you're an idiot.

I can glance at those links and see IMMEDIATELY that it was Farnell without "parsing". My brain parsed it as a whole image.

You must read slowly and phonetically only.