RE: (ET) E20 and Cruise Control / Power Pulse Button

["Markus Lorch" <mlorch vt edu>]

Chris,

I think you hit the nail on the head. I did some test driving today 
with all the comments (thank you guys) in mind and monitored the
behavior. The relay clicks only in speeds 5-8 and only when I am
accelerating or when I am slowing down due to an uphill climb. 
The clicking starts when the power use gauge is about halfway 
into red. There is no noticeable speed reduction, which makes sense
as the motor was either trying to speed up (and drew too much 
current) or the motor was (already) slowed down due to an uphill 
climb and prob. could not sustain the speed with the weakened 
field. 

It seems to work as designed and happens only when I
floor the pedal or try to go full speed over my lawn 
with a slight increase. When its flat or slightly downhill 
I can go all speeds with the amperage staying in yellow.

In the first 4 speeds there is no relay clicking, even if the 
power use gauge goes to the right end of the red area (if I
take of by flooring the pedal in D2) 

Thank you all for commenting. 

Btw, I just got my new soneil chargers. Hooked them right up
and will see how the batteries look in the morning.

Markus



> -----Original Message-----
> From: elec-trak-bounces cosmos phy tufts edu 
> [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of 
> Christopher Zach
> Sent: Donnerstag, 29. April 2004 12:51
> To: Jeremy Gagliardi com
> Cc: elec-trak cosmos phy tufts edu
> Subject: Re: (ET) E20 and Cruise Control / Power Pulse Button
> 
> 
> Well, the E20 does have a current limiter, however it works 
> as follows:
> 
> In speeds 1-4, the current limiter does nothing really. 
> However when you 
> go to speeds 5-8 (with field weakening), the armature draws 
> more current 
> under load. Without a control of some sort you could overheat 
> the motor 
> fast on a hill.
> 
> To fix this, the E20 has a small circuit that basically compares the 
> current going thru the main shunt to a predetermined value. If the 
> current thru the shunt exceeds that value a transistor turns on and 
> bypasses the entire field weakening circuit by dropping the FW relay. 
> With the FW resistors bypassed, the field gets full power, armature 
> current goes down and the tractor essentially goes to speed 4 
> (full power).
> 
> That might be your problem; in D2 the motor is working pretty hard. 
> Perhaps the card logic is having problems and is causing the field to 
> oscillate back and forth. Does this only happen in high 
> speeds (5-8) or 
> in any speed?
> 
> Chris
> 
> 
> Jeremy Gagliardi com wrote:
> 
> > On Thu, 29 Apr 2004 12:24:28 -0400, "Perry Cain" wrote:
> > 
> >>I thought I had the same problem.  Seemed to happen in D2.  
> Looked at
> >>everything.  Actually, it turns out, that when going that 
> speed, the seat
> >>was bouncing, turning the seat switch off and on very quickly....
> > 
> > 
> > That may explain why I've never had that chattering relay 
> problem in D2.  On my
> > E20, if the seat switch goes off, even for a fraction of a 
> second, I have to
> > start from throttle "0" before I can go again.  It 
> completely resets the system.
> > 
> > E20
> > Bethesda, Md
> > 
> > 
> > (---------------------------)
> >  mailto:Jeremy Gagliardi com
> >  http://Jeremy.Gagliardi.com
> > (---------------------------)
> > 
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