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Best way to wind a transformer?

I'm building another fluorescent light inverter thing, and it says to use a ferrite rod as the transformer core. Any advice on how to do this? (It doesn't have a bobbin) Also should I put insulating tape between the layers on the secondary? Last time I built one of these on a standard bobbin it blew the secondary in like 10 minutes. Also what size heatsink would be advisable for the tip3055? Heres the inverter schematic (http://free-schematic.blogspot.com/2010/04/20-watt-fluoro-inverter-used-tip3055.html)

Thanks in advance -Ray, KD2JID


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#1 Use what's called magnet wire. it's Formvar, a varnish, insulated. The primary should be closest to the rod. The secondary on top. No insulation between windings. make the wire as close as possible. Remember,
the same direction.

There is a big difference in wire size, so a layer of fish paper might help a little bit

There is a mounting kit for the TO220 that contains a thermal washer (Silpad), a screw, a nut and a bellville washer. the washer is a critical component. it has a dome shape. A Silpad will not require thermal grease. Other washers might.

remember to remove the 2.2 ohm resistor after testing.

there is a 13 turn feedback winding. make sure the turns are equally spaced. I'd probably use the larger diameter wire.

The polarity of the windings are not marked. i think the FB winding will make a difference. have some extra 2.2 ohm resistors (metal oxide)

You might be able to use a low speed drill, but you would have to support it at both ends. e.g. a Live center in a lathe/

A 10cm long bar will break easy.

if you wound a toroid, you would use the manual winding tool which is a long piece of flat stock (10 cm or longer)that fits through the torroid and it has the wire loosely wound on it.

I remember doing 80 turns on a toroid.

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