28 Aug
2010
28 Aug
'10
3:59 p.m.
Hi Tony
First, to determine the number of turns. These are flyback so
the collector ( or plate voltage ) would not be enough. You'd have to
measure the peak voltage on the collector ( or plate ) and then use
the known voltage of the second anode.
This would give you the turns ratio.
This would, of course need to be done on a working coil.
Next to determine the wire sizes and the primary turns.
This is a distructive method. You just saw it perpendicular
to the turns. Counting the primary turns is usually easy
if the transformer is not potted. In this case, you'd need
to grind the ends on a belt sander until you can see the
turns separately You should be able to see the primary
turns.
As far as a vacuum, just use an old bicycle pump with the
plunger and one-way valve turned around. An old cast
pressure cooker would work well enough as a vacuum
chamber ( never to be used again for cooking ).
Rigging a lathe with a counter and you can wind the
coil.
These are all things I think you can handle.
Dwight
From: ard at p850ug1.demon.co.uk
As some of us know all too well, flyback transofrmers fail, and are often
next-to-impossible to get. So I have been wondering if it's possible to
make a replacement...
There would appear to be 2 parts to this.
1) Desigining the replacement. I think we can assume a schematic of hte
horizontal output stage it's going to be used in. But how do you
calcualtor the number of turns on each winding? Since the origianl is
likely ot be potted in epoxy (for HV insulation reasons), counting the
turns there is impossible.
Are there any good references (books, web pages, etc) on the desing of
such transoformes and/or the design of horizotnal output stages? I would
have thought something must exist, but I've never seen it.
2) Making the replacement. It owuld ahve to be vacuum pmpregnated, I
think. But I believe some model engineers who make internal combustion
engines make the own ignition coils (and vacuum-impregnate them?). Again,
any good references on doing this?
-tony