Re: (ET) I was woundering.

["Christopher Zach" <czach computer org>]

*laugh* There is that.

But seriously, my point is valid: In my opinion the Elec-Trak uses the 
right
amount of technology in the right combinations to make what one might
consider to be a perfectly balanced product. The batteries are tough, the
design is rigid, and it can rip stumps out of the ground. The speed control
is superior to anything in the other-lawn-tractor world with the exception
of the varidrive pulley systems on some lawn tractors.

What works for a tractor isn't necessarily the same thing that works for an
on-road automobile. For the car the design goals are much more complex. The
concept of variable speed control are important, as is the desire to make a
device that closely matches the experience of driving a "normal" car. The
requirements are different. A contactor based controller doesn't work too
well for a car because there are a large number of speeds that we drive on 
a
daily basis. One can ameliorate this by shifting gears, but that can 
require
a lot of shifting.

The focus is design the best solution for the problem at hand. For that I
praise the simple logical design of the Elec-Trak. And at the same time I
praise the logical low-maintenance design of a water-cooled AC induction
system for the Prizm.

Now, if I could put AC on the tractor.... :-)

Chris



----- Original Message -----
From: "Humphrey, Timothy" <HumphreyT neads ang af mil>
To: "elec-trak" <elec-trak cosmos phy tufts edu>
Sent: Wednesday, April 23, 2003 10:32 AM
Subject: RE: (ET) I was woundering.


> Now that's what I call open minded.
>
> On the EV list you are always talking about how much you like your Prizm
> with it's fancy AC Controller and all the bells and whistles an AC
> controller provides, and here you expound the virtues of the ET's
simplistic
> DC system with contactor controls.
>
> Can anybody else here recall anyone on the EV list (other than Lee, and
> David) that will praise both technologies with equal zeal.
>
> Good on ya, Chris.
>
> Stay Charged!
>
> Hump
>
> > -----Original Message-----
> > From: Christopher Zach [mailto:czach computer org]
> > Sent: Wednesday, April 23, 2003 9:47 AM
> > To: elec-trak
> > Subject: Re: (ET) I was woundering.
> >
> >
> > 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
> > >
> > >
> > >
> >
> >
>
>