Hello listers :
I just measured the resistance of two Lucas ammeters (both from 59
TR3A's, with the setscrew terminals), using fairly accurate digital
meters. Both are 1.2 milliohms.
Some quick work with a resistance table & calculator shows that a 50%
shunt (equal resistance) could be made from 5.5" of 14 gauge copper wire
(8.29 milliohms/meter) or 3.5" of 16 gauge copper (13.2
milliohms/meter). At 30 amps (50% of 60 amps total), the shunt will
dissipate 1.1 watts, which shouldn't be a problem.
Just for grins, I measured a 60 amp "no name" ammeter at 32 milliohms,
much higher than the Lucas.
Of course, "your mileage may vary" <g>
My apologies to the person who I suggested start with 4" of 14 gauge.
If anyone is still interested, I can probably borrow & measure a TR6
ammeter, but it might take a while.
Bill : Know of anyone in the area who might loan me one ?
Randall
|