Re: (ET) Elec-Trak ZTR

FWIW...I just tried my E20 tractor with mowing deck on a couple different slopes. My pwm controller is current limited to 120 amps and the rest of the E20's drive parts are stock. I weigh 175lbs.

In D1, I stalled at the bottom of a 45 degree hill just as the back wheels were starting up the slope. In L, I make it just fine, drawing a little more than half of the 120 amps (65 to 70??).

I did make it up the 35 degree hill at max speed in D1 but I was drawing close to maximum current (110 to 120??).

All the above was done with no field weakening. Also noticed was the battery voltage sag when drawing the high currents.

Does anyone know the recommended maximum discharge rate from these 6 volt batteries before they have too much voltage sag?

Tim

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

From: Markus Lorch

To: 'Mike Wallace' ; 'Elec-trak Discussion Group'

Sent: Saturday, July 10, 2004 8:37 AM

Subject: RE: (ET) Elec-Trak ZTR

Mike,

do you think you need more torque than the motors give you in D1 or D2? Looking at other ZTRs they are rather

fast so I would go prob. with the D1 ratio. Speed control should not be a problem as a modern controller can handle

this. Torque should be ok IMHO as now you also have two motors, so twice the power.

I think the L ratio is too low may depend on the terrain you are working on though.

Markus

-----Original Message-----
From: elec-trak-bounces cosmos phy tufts edu [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of Mike Wallace
Sent: Saturday, July 10, 2004 12:24 AM
To: Elec-trak Discussion Group
Subject: (ET) Elec-Trak ZTR

Has anyone ever tried to figure out what the final drive ratios are in a large frame tractor?

I jacked up the back wheels and had the wife turn both of them at the same time and exactly one revolution, while I counted the revolutions of the motor pulley on a C-185.

The numbers I came up with are as follows:

    LL - 266:1

      L -   90:1

    D1 - 50:1

    D2 - 34:1

Now if those numbers are anywhere near right, what would you suggest as the optimum single drive ratio if a guy wanted to make an Elec-Trak ZTR. I figured on using (2) E14 or maybe E15 drive motors hooked to each drive wheel via right angle worm gear speed reducers?

Anybody got any thoughts?

Mike Wallace
Glasgow, KY

_______________________________________________
Elec-trak mailing list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak