All,
I know some of you have done this and I just
wanted to share my findings. I just "acquired"
an older, large chipper/shredder with an 8 HP
B&S combustion engine. A neighbor of my friend
wanted to toss it out but I couldn't stand by
and watch him do it. None of us had a way
to move it though and it was about 1 mile from
where my house is. So I strapped an emergency
car light (one of those that flash red, it was
already dark) to the back of my E20 and drove
through the neighborhood (the mower deck still
on, as I was too lazy to take it off) ... it was
great going down that 0.5 mile hill with
the cruise control on and full regenerative
breaking. I didn't dare to take it out of
gear (something I had done with larger
tractors when I was a foolish teenager)
but rather enjoyed the smooth ride on
asphalt.
Ok, long story, I got there hooked the
chipper up and drove it back. It was a nice
ride, even though driving on asphalt the
tractor feels much slower than in my bumpy yard.
The information i got with the chipper was
that it needs carburator work and was
missing an exhaust.
Tonight I did fire the chipper up with the
combustion engine. Poured a bit of gas in
there (still got stinky fingers), fiddled with
the carb. and took the air filter off.
About 10 good pulls and it ran. Its flooding
the carb but with the gas valve almost closed
it sort of works. However it has no muffler
(other than an old pineapple can) and is really
loud. Its not spinning too high, i would guess
2000-3000 rpm. I wanted to do this test to see
how/if it worked in general and would chip
wood. I was happy with the results.
Now I thought I buy an AC motor and have it
hooked up to the grid. Mike Wallace suggested
to look at an E15 drive motor or similar. So I
looked at the motor performance curves that Mike
has (posted on http://www.econogics.com/ev/etsites.htm)
This is great information. I didn't expect the
E20 motor to deliver 35 lb-ft (at 400A!). And the
E15 motor goes up to 25 lb-ft. pretty cool.Even
the largest B&S engine (18HP) that jackssmallengines
has specs for doesn't go above 30 lb-ft. Now I
see how they could claim that the E20 has the torque
of a 20HP gas.
I wanted to see if an E15 motor would do for the
chipper so I checked jackssmallengines for the
recommended B&S replacement ICE for the chipper
and they propose a 10.5 HP that delivers 16 lb-ft
peak at 2700 rpm. The E15 motor just about maxes
out at 2700 rpm with full field and would provide
its maximum torque of 25lb-ft. (and draw about
280 A under full load which is equivalent to
about 10kw or 14HP of input, prob. around 11HP output)
... so the point being the E15 motor could provide
approximately twice the torque than the 8HP engine
the chipper has right now. I think thats gonna be
beefy!
Well - I am pretty hyped about it so I just thought
I share it with y'all.
Markus
----------------------------------------------------------------
Markus Lorch
Department of Computer Science Phone: +1 540 231 5914
Virginia Tech, m/c 106
http://www.econogics.com/ev/etsites.htm Fax: +1 540 231 6075
Blacksburg, VA 24061, U.S.A. http://people.cs.vt.edu/~mlorch
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