Re: (ET) I was woundering.

["Bob Murcek" <rmurcek geisinger edu>]

Here are a couple of possible reasons:
- Really smooth speed control at very low speeds.  Might be useful for 
towing large loads.  An electronic controller provides nearly full torque 
even when starting out at a creep.
- Regenerative braking.  If you have a controller that can do this, you 
might get longer battery life if you have really hilly terrain.

>>> "Christopher Zach" <czach computer org> 4/23/2003 9:46:43 AM >>>
I'm curious as to *why* to replace the controllers in the Elec-Trak.

The shunt wound models (well, the E15/E20's) have a total of 8 speeds and 4
gears. That's 32 possible forward speed settings between 0 mph and 8 mph. 
Do
we really need more granular control? Personally I drive mine with two
speeds: cruise speed for mowing (in L) and "run around" speed at full blast
(also in L). My gas tractor has only one speed; mow (you can't cut the
throttle since it spins the blades, and gear-shifting requires a full stop.
Really fustrating)

As for reliability, the relays and contactors seem to be reliable. They
complain a bit at times, but that's more to the fact that the relays could
use some cleaning and TLC.

An argument could be made that the resistor banks aren't efficient, but if
I'm going that slow I typically will shift into LL and run the motor at
cruise speed.

All in all I can't see much reason for an electronic control system. The
electronics for the E20 seem to be limited to keeping the field weakening
function from burning out the armature, and that's about what we need.

Chris


----- Original Message -----
From: "Jim Coate" <jbc coate org>
To: "elec-trak" <elec-trak cosmos phy tufts edu>
Sent: Wednesday, April 23, 2003 8:58 AM
Subject: Re: (ET) I was woundering.


> I agree with the concept, and we are an inventive bunch... but unless
> someone is looking for a task, plenty of 21st century controllers
> already exist that have proven by use in golf carts and industrial
> settings. Curtis being the standard for electronic controllers in this
> size, and AllTrax being the new kid on the block (although I haven't
> checked if AllTrax has a model to match the ET needs).
>
> ThompsonG DFO-MPO GC CA wrote:
> > Hi
> > It seems to me that ETs with 21st century electronics, some TLC,  new
> > bearing, grease and new rear battery boxes could last another 30 years
> > without a problem. Also with a source of new electric works :-)  more 
> > ET
> > could be rescued and perhaps generate more interest in the great EV
world.
> > It seems to me that guys with EVs would be very interested in electric
> > landscaping and snow removal etc.
> > So, I just though I'd send this up as a trial balloon to see how much
> > interest it would generate.
> > Harry Landis and/or Rod Hower would you consider taking Rod's 
> > controller
> > design and modifying (I suspect this is just a simpler version of
current
> > design) it for a E12 and B-145 and then either selling the CKT board,
the
> > plans or the entire unit.
> > I would be willing to buy one (if it's the plan)  or several (if it's
the
> > board or the entire assembly) of these and in fact fund the development
of
> > the fist prototype. I think there a real need to update, at least our
> > "working ETs".
>
> _________
> Jim Coate
> 1992 Chevy S10
> 1970's Elec-Trak
> http://www.eeevee.com 
>
>
>