Actually, an ammeter is an ammeter and a voltmeter is a millameter with some
resistance in line. All of these analog meters work on the basis of current
flow though the meter coil.
Although some ammeters have shunt resistances to divert most of the current
around the coil, I believe that the TR3 ammeter does not. The entire current
runs though the meter and creates the magnetic field which moves the meter
pointer.
David Massey wrote:
> Message text written by dyaarl anderson
> >What would cause my AMP gauge to burn up ? Old age, too much juice,
> voltage regulator screwed up or all of the above? Any ideas out there.
> Thanks
> <
>
> Dyaarl
>
> An ammeter is really a volt meter with an internal shunt. Current passes
> throught the shunt and the volt meter reads the resulting voltage.
> Obviously, the voltage developed by the shunt is very small (or else the
> system voltage would fall way off as electricla loads are switched on) and
> the voltmeter reads in fractions of a volt.
>
> If the connections to the internal shunt were to become less than ideal
> more and more voltage would develop and the volt meter part would become
> overloaded and fail.
>
> So, old age is a possibility.
>
> Another possible culprit is a wiring short to ground. Was there a short
> to ground where battery current was shunted to ground. The current level
> sufficient to burn up an ammeter would also melt the insulation on the
> wires. Look for evidence of melted insulation.
>
> If you find melted insulation find and fix the short. If you don't, chalk
> it up to old age.
>
> Good Luck
>
> Dave
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