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Re: Current sensing
- Subject: Re: Current sensing
- From: "David Roden" <roden ald net>
- Date: Sat, 2 Jan 1999 21:38:20 -0500
- In-reply-to: <001b01be36b0$83f88980$e0f0accf@Maximum.ultranet.com>
- Sender: owner-elec-trak cosmos5 phy tufts edu
"Max Hall" <maxo iname com> writes:
> problem is, how do you get the resistance to be nice and small, and yet
> stable, so you can measure current without pissing away power?
You buy a high current shunt. The EV parts dealers (Electro Automotive,
KTA Services, and so on) sell them, and you might be able to find them at
a local industrial vehicle shop.
A shunt is a calibrated low resistance. The usual EV shunt is low enough
in resistance to generate 50 millivolts (mv) at 500 amps. They are
available at other currents, but 50 mv is the standard. All you need
then is a 50 mv full scale voltmeter. With a 500 amp shunt, each mv on
the meter is 10 amps.
David Roden THE VIRTUAL PD
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