Re: Power factor ? Roll your own.

[Lee Hart <leeahart@earthlink.net>]

Rich Rudman wrote:
Lee Hart wrote:
>> Toroids are great performance-wise, but hideous to wind. I'd
>> recommend E-I laminations for a home-built inductor. You can
>> wind 10 in the same time as one toroid.

> I doubt that Lee, since it took me just a few minutes.

If you can wind a toroid in a few minutes, you are in the wrong
business! Wind toroids for a living! :-)

> Getting steel lams to play with is a LOT harder than a few cores that
> are nicley enameled and smoonth and don't make me BLEED! I hate doing
> E-I lams. Humming buzzing dirty rusty Razzor blades!

You can buy premade laminations, just like other cores. Inductors are
easier than transformers, because you can just stack all the E's on one
side, and all the I's on the other, so it is easy to shim for the
desired inductance.

Yes, they will "sing" to you if there are loose laminations. Bolt 'em
tight or dunk it in varnish to glue them all together.

>> Isn't that [wire size] a little thin?

> I suppose you are right... That's why I tagged you, to learn something
> I didn't think I needed to know. Next problem is square profile wire...

I'd use a larger gauge, but stranded wire. MUCH easier to wind, and it
keeps the efficiency toroids are known for. If flexible enough, the wire
can be wound on a long thin stick, which will poke thru the core to
simplify winding. You can even use PVC insulated wire if it's large
enough to keep the temperature rise down.

How are you going to mount that toroid? It's tough because they are
heavy, the entire surface is covered with wire, and anything metallic
that goes thru the hole in the middle counts as a turn.

Here's a tricky way that also simplifies winding. Make a PC board. Strap
the core to the board with pieces of bare copper wire. If you want 25
turns, use 25 pieces of wire. The wire connects two pads on the board,
and the foil on the board connects all the wires in series. At your
current levels, I'd bend the ends of the wires so they are parallel to
each other. Dip the board in a solder pot to make all the connections.
-- 
Lee A. Hart                Ring the bells that still can ring
814 8th Ave. N.            Forget your perfect offering
Sartell, MN 56377 USA      There is a crack in everything
leeahart_at_earthlink.net  That's how the light gets in - Leonard Cohen