Re: (ET) I was woundering.

[Seth <vze3v25q verizon net>]

Greater range. At any speed where you are weakening the armature
current, you incur a loss in the resistor (the same for the field, but
the current is lower). If this is done by PWMing the current, then it is
much more efficient and should get better range.


Oh yeah, it's cool too :)

Seth

Christopher Zach wrote:
> 
> 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
> >
> >
> >

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