Re: (ET) Chipper conversion, ET motor power evaluation

["Dave & Deb" <daveb drizzle com>]

cool be sure to keep us posted!
Dave

> 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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