Re: (ET) Amp draw

Good data Larry.

Actually I think I remember measuring the ammeter to be closer to 90mV full scale, but figured it must really be 100mV since that would be a common range. Well anyway we're within 10%.

The voltmeter is interesting data and I've never checked mine. Mine always seem to read low, so I shoudl do a real check on it - maybe I have a 'resistive' cutout switch.

- SteveS

----- Original Message -----

From: Elie, Larry (L.D.)

To: 'SteveS' ;

Sent: Friday, September 26, 2003 3:41 PM

Subject: RE: (ET) Amp draw

Here's some old data I took back in 2001 on new (?) meters:

Volt (fuel) meter

The following is a table of needle reading and measured voltage for a gauge in correct working condition. 'E' stands for empty, green is normal operating condition, with 'F' standing for full and white is charge only range. The numbers are when the needle splits the line between colors.

Needle just moves 19.8V

Bottom of red 26.7V

Top of red, bottom of green, "E" 33.1V

Top of green, bottom of white, "F" 39.0V

Top of white, bottom of upper red, 45.5V

Top or upper red 47.3V

Current (load) meter:

Shunt resistance is .000658 ohms, or 20" of #6 copper.

Bottom of green = 0 mV. (0 amps)

Top of green, bottom of yellow = 36 mV (55 amps)

Top of yellow,bottom of red = 64 mV (97 amps)

Top of red, = 90 mV (137 amps)

So your 100 mV guess was pretty close; they probably used one and then printed the scale a bit off.

Larry Elie

-----Original Message-----
From: SteveS [mailto:ssawtelle fcc net]
Sent: Thursday, August 21, 2003 7:37 AM
To: elec-trak cosmos phy tufts edu
Subject: Re: (ET) Amp draw

Don't think I've seen a reply on this so I'll give you my best shot.

From measurements I've taken, I believe the meter (at least on E12S) is 150A full scale. I think it's also a 100mV meter, so the shunt in the tractor is .1V / 150A = 0.67mOhms. This squares pretty well with the resistance of the 20" 6AWG wire used as a shunt in many models: .41Ohms/1000ft /1000/ 12"/ft * 20" = 0.68mOhms

So you can use a 100mV meter movement or your DVM on the mV scale and scale up using 100mV = 150A.

Data logging on my E12S while mowing has shown a few spikes up near 100A, but the average is well below that.

Hope that's what you are looking for...

SteveS

E20

E12S

----- Original Message -----

From: Ferguson Apiaries

To:

Sent: Monday, August 18, 2003 9:12 PM

Subject: (ET) Amp draw

Hi

I am interested in the amp draw for a 15 et. I burnt out my meter on the tractor during conversion and was wanting to know the amps without buying a expensive meter.

www.fergusonapiaries.on.ca
Ferguson Apiaries
Hensall, On
519-236-4979

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