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Re: (ET) Chipper conversion, ET motor power evaluation
Just curious, where were you thinking of getting the "more than 36v from".
If you are adding a 12v batter in series with the field then I could see
going this route..
BUT, if you have more Deep Cycle batteries that you are planning to use,
then I would just power the whole motor, both series and field with the
higher value, say 48 or 54 or 60 or whatever.
I have the same problem on my sawmill. The ET drive motor has the power to
cut the logs, but not in the rpm range I need it to be in. If I change the
pulley ratio to slow the motor down(more torque,more current, more blade
speed), then I will kill my batteries sooner. I was thinking of adding
more batteries, to go with a 72volt system, to increase the available HP
at a higher speed. I think the drive motor will handle 72v without a
problem. I sure hope so, because I'm powering my kids Jr. Dragster with a
snowthrower motor at 72v(next spring).
I really want to make this thing work with the ET. But, practicality says
to use an ICE, although I'm not ready to go there yet. B4 I revert to ICE
I will string 150ft of 4ga, and run a 240vac 5 hp compressor motor. $180
for the wire, $125 for the motor. (or move the mill closer to the house
and save a little money on wire.)
I wish I had an on road EV truck, then I would power the mill with that. I
don't want to prematurely kill my ET pack just because I can.
Stay Charged!
Hump
>
>
> >
>
> Pieter,
>
> thanks for your thoughts. I may have to put a larger pulley on the E15
> motor
> to compensate for this phaenomena. With full field the
> E15 motor would still turn at about 800 rpm if a braking force
> of 25 ft-lb is applied according to the curves. If I assume we h eave to
> have 1500 rpm to be useful (I guess the ICE was running 2000-2500
> rpm) then with full fueld the E15 would still develop 15 ft-lb which is
> about the same as the ICE. If the RPM of the chipper
> wheel is not high enough I could always put a larger pulley on the motor
> to
> comensate for the different torque characteristics. I have to watch out
> though not to overspeed the chipper when there is no load applied. Maybe
> I
> need to do more tests while the ICE is still mounted with different load
> scenarios. Unfortunately with the bad carburator its kinda tough to say
> if
> the motor is running at its typical speed.
>
> A question: What would happen if I applied more than 36V to the field,
> then
> more than the rated 1.9A would flow though the field and make it
> stronger.
> Would it also mean that the motor starts out with a smaller max. rpm in
> no-load situation has less of an rpm cave-in under load - i.e. the RPM
> curve
> would be more flattened. This might alleviate the overspeed concerns in
> light-load situations.
>
> Well back home we have a saying "to try it out is better than to study
> it",
> so I think I'll just try it out and see how it works out .... back to
> work
>
> Markus
>
>
> > Another thing to consider in re-powering is the speed at
> > which the engines
> > develop maximum powr. Electric engine develop maximum torque
> > at stall (0
> > RPM). Gas engines don't - I suspect the chipper gas engine
> > might develop
> > maximum torque between 1500-2500 RPM (??). In any case, this
> > difference
> > will cause them to perform quite differently in an application like
> > chipping even though the two power sources might have the same HP and
> > torque ratings. A chipper developing maximum torque at 0 RPM
> > isn't very
> > useful.
> >
> > At 08:55 PM 9/29/2004, Markus Lorch wrote:
> > >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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> > >Elec-trak cosmos phy tufts edu
> > >https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak
> >
> >
>
>
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