Re: (ET) walk behind electric tractor?

["SteveS" <ssawtelle fcc net>]

Reminds me of the old "Peak IHF Music Power Rating" for advertising power
out on early stereo amps! (or do I date myself?)

- SteveS
E12S
Leesburg, VA


----- Original Message -----
From: "Elie, Larry (L.D.)" <lelie ford com>
To: <jbc coate org>; <>
Sent: Friday, February 14, 2003 10:41 AM
Subject: RE: (ET) walk behind electric tractor?


> Before you get too excited, it's 1/2 hp folks.  Rule of thumb; an 
> electric
motor can replace a gas engine of twice it's hp (assuming the electric hp 
is
'honest'...) so it should be equivalent to a 1 hp tiller... hmm... too 
wimpy
for much work.  The smallest Troy-Built Pony is 3.5 hp I think.  The reason
of course is that the cells are pretty small to charge anything.  BTW, many
electric hp ratings are trash; Sears is probably the worst.  I have used a
'4.5 hp peak' saw that was 12 Amps at 110v.  Now 12A * 110v = 1320 watts.
760 watts is 1 hp IF everything is perfect; it isn't.  Typically it takes
1000 electrical watts to produce 1 hp for small AC motors.  They claim the
peak wrong; they use peak voltage * peak current (you are only entitled to
use RMS values unless you can manage square-wave current) and STILL don't
get those numbers.  They take that value, add in the inertia of the motor 
to
stall ('brake' hp, sort of) and factor in that, then they round up.  That
4.5 hp pe!
> ak sears saw is probably 1 to 1.2 hp.  Now I expect this tiller is really
an HONEST 1/2 hp, but it is still a bit wimpy to do serious work.  The GE
big tiller runs 70 A at 36 V continuously, and the breaker trips at 100 A 
at
36 V after a few minutes (you can go way over 100 A for over a minute
though) so I get around 3500 watts; still only about 4 to 5 hp, which
compares very well to an old Sears tiller I had behind a tractor of the 
SAME
width that used an 8 hp gas engine; the old 2-1 rule.  I don't know the
rating of the little GE tiller.
>
> Larry Elie
>
>
> -----Original Message-----
> From: Jim Coate [mailto:jbc coate org]
> Sent: Thursday, February 13, 2003 10:11 PM
> To: elec-trak cosmos phy tufts edu
> Subject: (ET) walk behind electric tractor?
>
>
>
> While searching for electric tractor information on the web, I stumbled
> upon the "Sun Horse" walk-behind electric tractor. There are a variety
> of tools to plow, seed, cultivate, and haul, and the variable-speed
> drive reportedly allows for precise "surgical weeding".
>
> Has anyone seen such? This is a new one to me.
>
> See http://www.freepowersys.com/shorse.htm
>
>
> _________
> Jim Coate
> 1992 Chevy S10
> 1970's Elec-Trak
> http://www.eeevee.com
>