Re: treadmill motors (was High-Voltage P

[LEE A HART <XURQ03A@PRODIGY.COM>]

Try this. Take TWO motors, and connect their shafts with a coupler (or piece
of rubber hose, etc). Drive one as a motor. Load the other one with a
resistive load (or batteries or something). Measure the power input (volts x
amps) and the power output (volts x amps). Compute efficiency as:

        Vin x Iin x Eff#1 x Eff#2 = Vout x Iout

If motor #1 is the same as #2, their efficiencies are equal. So

        Eff x Eff = (Vout x Iout) / (Vin x Iin)
        Eff = sqrt [ (Vout x Iout) / (Vin x Iin) ]

For example: Vin = 100vdc, Iin = 10amps, Vout 90vdc, Iout = 6 amps. So

        Eff = sqrt [ (90v x 6a) / (100v x 10a) ]
            = sqrt ( 540 / 1000 )
            = sqrt (0.54)
            = 0.735 = 73.5% for each motor

This will provide a quick-and-dirty measurement of what the efficiency really is
 .

Lee Hart                     If you would not be forgotten
4209 France Ave. N.          Soon as you are dead and rotten
Robbinsdale, MN 55422 USA    Either write things worth the reading
phone (612) 533-3226         Or do things worthy of the writing
e-mail XURQ03A@prodigy.com   (Ben Franklin, Poor Richard's Almanac)
Re: treadmill motors (was High-Voltage P