Re: (ET) shunt

["David Roden" <etpost drmm net>]

On 8 Jul 2015 at 6:36, Harold Zimmerman - Clean Power Supply wrote:

> A digital voltmeter can be used to verify my recollection that the
> meter is 50 millivolts at full reading. 

That's a typical number for shunt ammeters.  Most but not all "real" 
shunts 
(not lenghths of wire ;-) are calibrated for x amps at 50mv.

So taking that as correct and figuring the meter calibration :

No. 6 copper wire has a resistance of 0.403 ohms per 1000 ft.

The shunt is 0.0000335 ohms per inch * 18.5 inches == 0.00062 ohms

Ohm's law I = E/R

0.050v / 0.00062 ohms = 80 amps

So, full scale on the power use gauge (ammeter) is about 80 amps, which 
also 
seems reasonable to me.


David Roden - Akron, Ohio, USA

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