> I'd purchased a used fuel gauge for my TR3A. Trouble is, the fuse to F3/F4
> kept blowing. I've isolated it to the gauge by disconnecting output to the
> fuel gauge and running an inline fuse from a direct power source, bypassing
> the stabilizer.
Terry, a stock TR3A gauge does not require a stabilizer, and having one will
make the gauge act crazy. Do you have a TR4 gauge instead ?
> I tend to think this is a fuel gauge problem, but I can't figure out why a
> short to ground within the gauge would not short regardless where the leads
> are attached, since really a gauge is only a simple resister, isn't it?
I can't make any sense of this statement at all. A short to ground is a short
to ground, no matter what the rest of the circuitry is. And no gauge is a
"simple" resistor, although all of them have resistance ... they are always
arranged so that running current through the resistance causes some side effect.
An original TR3 gauge has two "resistors", which are actually coils of wire that
form electro-magnets, but have a fairly high resistance. A TR4-6 gauge is a
single "resistor", again actually a coil of wire that forms a heater. (The heat
causes a bimetal strip to deflect and move the needle.)
No matter which gauge you have, an internal short to ground at one terminal will
only blow the fuse if that terminal gets the supply voltage.
Randall
=== This list supported in part by The Vintage Triumph Register
=== http://www.vtr.org
|