Re: (ET) first mow

["Christopher Zach" <czach computer org>]

Correct. With less than full field, you draw more current through the
armature and the tractor goes faster.

However if you go to speed 1,2,3 the tractor should be locking in full 
field
anyway. Speeds 4-? start cutting in the resistors to weaken the field
current/voltage.

In speed 1-2, armature current is restricted by the two resistors in series
with the armature. When you go to speed 2, there is a click and one of the
resistors is bypassed by a solenoid. Go to speed three and the second
resistor is cut out by another solenoid.

Start the tractor in speed three, then drive it around the yard for a bit.
Then hop off and quickly pop the hood. Hold your hand over the front of the
charger; see if you feel any heat from the resistors. If you are in speed
three, the resistors should not be hot.

Chris

----- Original Message -----
From: "SteveS" <ssawtelle fcc net>
To: <elec-trak cosmos phy tufts edu>
Sent: Friday, April 26, 2002 10:36 AM
Subject: Re: (ET) first mow


> If I am not full field (as I suspect), would that have a large effect on
> motor power? I've been reading up on electric motors (I dodged the 
> electic
> motor class in college - "I want to build computers, not motors!" - now
it's
> payback time) and am trying to better understand how these things work.
>
> - SteveS
>
>
> ----- Original Message -----
> From: "Christopher Zach" <czach computer org>
> To: "SteveS" <ssawtelle fcc net>; <>
> Sent: Friday, April 26, 2002 10:18 AM
> Subject: Re: (ET) first mow
>
>
> > Steve:
> >
> > I have noticed that my E20 mows best in L gear, speed 4 (full current,
> full
> > field). In D or D2, it tends to slow down on steep hills and the 
> > battery
> > voltage drops which slows the speed of the deck motors.
> >
> > Chris
> >
> >
> > ----- Original Message -----
> > From: SteveS
> > To: elec-trak cosmos phy tufts edu
> > Sent: Friday, April 26, 2002 9:11 AM
> > Subject: (ET) first mow
> >
> >
> > Well, my snowplow worked great this past winter - we had no snow! But
> since
> > I took so long to get the mower deck rebuilt, the grass took off. So
this
> > past weekend I finally did some real Elec-Trak work mowing the yard.
Ahh!
> > The front mount mower takes a bit of getting used to, but I like it.
From
> > what I have read, I was worried that the rear disharge mower wouldn't
cut
> > well in the long (and wet) grass. But it did a good job and rarely
bogged
> > down. I really like how easy cleaning out deck is!
> >
> > Got a question though. I mowed in the higher of the two low gears and
the
> > elec-trak slowed a lot going up small slopes. Mower speed stayed about
the
> > same, so I think the batteries were up and I never went past mid-dial 
> > on
> the
> > amp gage. One clue is that when I shift (this is an E12S) the speed
> forward
> > from stop, I hear the click when I go to the 2nd position, but not to
the
> > 3rd position. I also don't notice a speed change between the 2nd and 
> > 3rd
> > position. So I'm guessing I have bad connection somewhere. Coudl this 
> > be
> the
> > cause of my lack of uphill power?
> >
> > Thanks,
> >
> > SteveS
> > E12S
> >
> > BTW, the mower deck has an eerie bagpipe-drone-kinda sound - I guess
from
> > the small speed differences of the three motors. It's interesting.
Reminds
> > me of riding in multi-engine prop planes (long time ago).
> >
> >
>
>