What kind of tape can you use for insulation between primary to secondary of flyback transformer. I know mass produced professional designs use a 3M specialty tape. What I'm looking for is a tape I could pick up at Staples or some office supply store or hardware store.
The vinyl electrical tape I can find is only rated for 600V and 80C MAX TEMP.
Is there a commonly available tape that is good for higher temp and offers higher insulation? I've read of people using a mylar tape is there a brand name ,type anyone could recommend?
I like using 3M #56 polyester tape. I think you can get it from Newark, but you'll need to cut it yourself to proper width. If this is for commercial use, there are companies out there that will precision slit the tape for you. See if you can find some China knockoff tape.
That is the product line. There are actually several vendors for that
3M tape, and even other makers, but 3M seems to be the most widely used by the industry.
You should utilize a slightly wider tape than the bobbin spool width. (about 40 mils) and you should never wind all the way to the bobbin face with each layer of wire. There should be several wire widths for fine wire. Larger wire will not likely give wire insulation issues because of the few number of turns. Never place more than about 150 turns per layer with fine wire (no random spool fills). Without insulation between turn
151 (approx) and the starting series of turns, the voltage difference can/will cause a breach of the insulation and fail the xformer. Finally vacuum impregnation with on of these if high repeatability and reliability are desired:
AC-43 is a common choice. It boils in a vacuum, so you have to bring it up slowly until that stops (it will eventually), then you can bring it up to nearly a full (industrially speaking) vacuum.
Then bake them out. (you should bake at 60C for about a half hour before impregnation as well to eradicate water.
Bullshit. Most of the vendors that *do* offer custom slit widths also have a huge line of standard cut widths.
The custom jobs are for those that know what they want, and are ready to make a minimum purchase and pay a tooling fee to get it.
Also, if one *does* make a single custom order, they do not require that they buy the whole roll, because they use the remaining bit to make standard cut widths. THEY buy those widths pre-cut in bulk, but when left with surplus on the lathe, they slit what remains up to sell as well.
I already posted the Farnell links, oh, great idiot that never reads the goddamned thread.
Folks around this industry use mils to describe thicknesses. Especially on things like tapes and films.
Granted microns can be used, but it has a lot less familiarity among folks, and also a lot less ability to look at something and declare a number. I can do mils fairly accurately, but calling something "1 mil" is a lot easier than trying to tag it with a micron numeric where the margin for error is higher.
Just one. I'm using an ETD29 core with Bobbin. I've made several transformers for LVDC less then 50Vrms.This is my first transformer from scratch for a line powered supply. I usually just buy or get samples from places like coil craft, but I want a multiple output flyback 50W small light weight and I've got this down too fitting into a 5" x 3" x2.2" in enclosure. I know I could buy one for $50 to 100 plus but that's no fun;-)
I will be the only one using it. Its main purpose is to save bench space and to save me the hassle of having to continually dig out 317's
7812 or 7805's when I'm working on something that requires multiple voltages.
So its not going to be tested for EMC compliance (but I do have a line filter) or Hi Pot tested etc.
I originally did it up to operate of my Bench top PSU with an EFD20 core/ bobbin set (for 24W ) but I want to be able to eliminate the larger Bench top PSU so I don't have so much clutter on the bench.
Eventually I'll get around to building a half decent sized bench, but I just finished installing and painting seven new interior doors. That's my renovating fun for a couple of months anyway's. ;-)
I just got some hollow mdf doors, I kept my pine jambs I refinished them last year they turned out nice.
They actually look really nice after two coats of off-white semi gloss. They contrast well with the oak trim and pine jambs. I thought I might have made a mistake in not getting pine or oak doors $$ but it turned out well. There's enough wood in my house as it is.:-)
I cant complain for $250 after all is said and done.
Years ago for non critical apps, we used wax paper for layer insulation for winding multilayers..
We also had a back yard solution for potting coils that seem to work well. We would use a small jar of turpentine and place a soft rubber or PVC from something crap into it. Place a rag around the entry point to keep it from drying up while the base material was getting solidified into a pliable paste!. We'd used that to pot coils, do filling repairs etc.
Some where along the line, liquid tape sprung out from that..:)