Transformer insulateing tape?
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From: Archimedes' Lever on 20 Jun 2010 02:48 On Sun, 20 Jun 2010 06:16:40 +0000 (UTC), Cydrome Leader <presence(a)MUNGEpanix.com> wrote: >Archimedes' Lever <OneBigLever(a)infiniteseries.org> wrote: >> On Sat, 19 Jun 2010 20:01:03 -0400, Jamie >> <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote: >> >>>Years ago for non critical apps, we used wax paper for layer >>>insulation for winding multilayers.. >> >> It was referred to as 'fish paper'. > >You would wind bobbin-less transformers on old newspapers if you wanted >to. No, I would not. > >The trick is to wind many coils at once next to each other, stop the >winder and insert a sheet of [anything] and wind the next layer and >repeat. Had you read the thread, you would have found that it was already covered. And the trick is not to "wind many coils". The trick is NOT to wind too many coils such that the mag wire insulation resistance gets compromised by the last turn being to near a lower voltage turn, such as the first or one of the early turns. Also, he is winding ONE unit, not doing a production run, and with small transformers, especially HV jobs, one at a time is only slightly slower but yield a far higher prime pass yield. > >When done with all of that, you saw or cut the individual windings apart. If you wind on a gang, you place several individual bobbins on the winder, and when you are done, they all come apart just fine. No cutting and certainly no sawing. >Trying to make one coil that way would be almost impossible as the >windings would slide off the edges and the insulating material would >collapse at the edges as well. It is a bobbin. It has bobbin faces, and if you do not know what a bobbin face is, you should not be expounding on transformer winding.
From: Wimpie on 20 Jun 2010 07:19 On 19 jun, 18:50, Hammy <s...(a)spam.com> wrote: > 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? > > This is for a 90 - 140Vac input flyback. Hello, A flyback needs low spreading inductance (to avoid excessive loss in the snubber). You don't want large barrier between your windings. Don't trust hobby tape, but try to get polyimide tape (brand name Kapton). It isn't cheap, but does the job. Best regards, Wim PA3DJS www.tetech.nl without abc, PM will reach me
From: Archimedes' Lever on 20 Jun 2010 07:40 On Sun, 20 Jun 2010 04:19:37 -0700 (PDT), Wimpie <wimabctel(a)tetech.nl> wrote: >On 19 jun, 18:50, Hammy <s...(a)spam.com> wrote: >> 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? >> >> This is for a 90 - 140Vac input flyback. > >Hello, > >A flyback needs low spreading inductance (to avoid excessive loss in >the snubber). You don't want large barrier between your windings. >Don't trust hobby tape, but try to get polyimide tape (brand name >Kapton). It isn't cheap, but does the job. > >Best regards, > > >Wim >PA3DJS >www.tetech.nl >without abc, PM will reach me Kapton is usually too thick and is cumbersome to wind with. the tapes that have been suggested are the right tapes to use. Polyester tapes will get the windings as close together as they can be.
From: Hammy on 20 Jun 2010 07:57 On Sun, 20 Jun 2010 06:07:33 +0000 (UTC), Cydrome Leader <presence(a)MUNGEpanix.com> wrote: > >This info helps quite a bit. > >For a single unit you might be able to scavenge the yellow tape from a >junked switching power supply from from a computer. Some peel apart if you >smash the ferrite, some don't. Do avoid plain electrical tape- it creeps >and "pressure" inside a coil with hundreds or thousands of turns can sink >right though it. > >Other sources of insulating material are in your junk pile. Those white >plastic sheets that replace fish paper to keep pins from hitting close >fitting chassies can be cut up and used. Junked computer power supplies >have lots of goodies like this inside them. > >It works fine for quick and dirty projects. secure it with scraps whatever >tape you can peel from a transformer or inductor and you're good. Thanks for the suggestion. I have two boxes of junk I can dig through. This is likely what I'll do next order to Newark I 'll get the proper tape for future projects.
From: Wimpie on 20 Jun 2010 08:24
On 20 jun, 13:40, Archimedes' Lever <OneBigLe...(a)InfiniteSeries.Org> wrote: > On Sun, 20 Jun 2010 04:19:37 -0700 (PDT), Wimpie <wimabc...(a)tetech.nl> > wrote: > > > > >On 19 jun, 18:50, Hammy <s...(a)spam.com> wrote: > >> 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? > > >> This is for a 90 - 140Vac input flyback. > > >Hello, > > >A flyback needs low spreading inductance (to avoid excessive loss in > >the snubber). You don't want large barrier between your windings. > >Don't trust hobby tape, but try to get polyimide tape (brand name > >Kapton). It isn't cheap, but does the job. > > >Best regards, > > >Wim > >PA3DJS > >www.tetech.nl > >without abc, PM will reach me > > Kapton is usually too thick and is cumbersome to wind with. the tapes > that have been suggested are the right tapes to use. Polyester tapes > will get the windings as close together as they can be. Hello Archimedes' Lever, I assumed that he needs the tape to separate primary and secondary windings only. For example: First half of primary turns in a layer two/three layers tape for safety insulation complete secondary winding two/three layers tape for safety insulation second half of primary turns in the last layer. In such an arrangement, kapton / polyimide is not that difficult to use (from experience), however I fully agree that suitable polyester tape can do the job (cheaper, easier to work with and easier to get). The reason for mentioning the polyimide was that he can be almost sure to have something that is OK. Before making final decision, he also has to find out the expected over voltage category and whether he requires single or double/ reinforced safety barrier in his transformer (as this also determines the required clearance and creepage distance). Best regards and thanks for the info, Wim PA3DJS www.tetech.nl without abc, PM will reach me |