7 Sep
2011
7 Sep
'11
12:52 p.m.
On 7 Sep 2011 at 19:04, Tony Duell wrote:
What is speacial about the transformer you need? I
thohght all you
needed was any fairly large non-torroidal transformer with a mains
winding. Take the core apart, reassamble all the E-laminations the
same way round and laeve out the Is. Run the mains winding from a
lower voltage (a Variac is handy here, it's about the only thing it is
handy for ;-)) since the impedance of the winding will be much lower
with the open magnetic circuit.
Microwave ovens are junked very frequently here and some have
fabulously large transformers in them (both high voltage and
filament, as well as some for the control circuitry.
With a power screwdriver, you usually can reduce a microwave oven to
sheet metal and electronics in minutes.
Many older laser printers and copiers have hefty transformers as
well. One instance I'm aware of was a big Panasonic laser printer
that used a large 220V power transformer to supply the various
electronics. It was, in turn fed by a 120V-to-220V step-up
transformer, equally large. Strange, but useful. Many old laser
printers are full of ZIP memory, interesting CPUs (68xxx, NS32016,
PPC). Definitely worth looking into--generally you can tell by the
weight of the unit what sort of power supply it uses.
--Chuck