To: mail11:;-at-cimcad.enet.dec-dot-com (-at-teslatech)
Subject: Wire, Caps
From: I am the NRA <pierson-at-cimcad.enet.dec-dot-com>
Date: Fri, 20 Jan 95 15:50:48 EST
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>Does anyone know where I can buy only about 2000 ft of #22 double formvar
>coated magnet wire. My local distributor wants me to buy 10 lbs. minimum -
>for about $100.00.
Allied lists two choices of #22, ($14-$24, depending on details) but
in 1 lb (ca 500 foot) rools. Splices are ungood. They might could
get bigger spools but the next step MAY be 10 lbs.... (Depending on
driving distance, it can pay to check the ditribs. Some times there is
a "pick up" provision that allows sensible minimum buys. And it looks
as if 2kft is going to run over the minimum anyway...) Motor winding
shops (Electrical repairs, yellow pages) might have an end roll. And
the all purpose electronic junque store usually has some odd rolls
(Lookslike needing about 4 pounds to make up 2kft...).
ACTIVE does not catalog magnet wire, but they are a "front" for
FUTURE, and can, i believe get ANYTHING from FUTURE, if given a few
days (Ive had 'em do it...) 800 ACTIVE 4. The number is off an
old catalog, may not be current... Worth a try.
Q of Caps
Detail workers with caps either pick a good material (Richard Q has written much
and well on this) or have the equipment to measure. I have vague knowledge of
doing it, need a signal source at frequency of interest measure voltage &
current and compare measured vs calculated values. Hard to sketch in a few
lines & I have not done it for caps, but for cables. Ideal cap is pure C at its
real value (close to its nameplate value). Disipative (low Q) cap will show
up as stray currents, and in phase, due to losses (cap current will be out of
phase). Can measure time for charge to leak off, looking for gross leakage, but
that is a quasi DC value, not much of interest. Pros have a "capacitor bridge"
that can measure this, with an on board oscillator. I think some of the
"lcr" meters that abound have loss/leakage functions as well. (But they may
operate at one frequency and the coil at another....).