From: "Mr23" <mr23 mn rr com>
To: "Archive, Elec-Trak" <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) Alltrax install!
Date: Wed, 6 Sep 2006 23:14:13 -0500
Okay, I'm 6 months late on this one...
I haven't looked at the physical placement, but, could a second switch be
put in place on the brake pedal that engages at the top of the pedal
travel, and applies the 'reverse' input to the controller?
Then, small pedal travel on the brake causes reverse selection to slow the
tractor, limiting pad use; further travel applies pads; max travel gives
"stop now" functionality described below.
Comments?
After nearly 2 years, I'm finally getting around to putting my controller
in.
Been busy, but part of the reason was laziness to source the resistor and
diodes in the diagram.
Now, after reading some back-postings, I find people are installing fuses.
Are these really necessary? And why one each on the Pins 9 and 10, when
just one is needed on the other size of R1 ?
-Chris
----- Original Message -----
From: Mike Wallace
To: ralphgv talkamerica net ; Archive, Elec-Trak
Sent: Friday, February 24, 2006 12:25 AM
Subject: Re: (ET) Alltrax install!
Ralph said,
"A while back several people (including me) wrote in about the brakes
grabbing when we tried to slow down a little bit. Now I see it is the
motor that is stopping us. I have a steep hill in back of my house with no
way to go around it. The tractor speeds up going down, and when I touch
the brake pedal I slow down for about a foot then the wheels lock up. The
tractor tears up the grass and will start sliding sideways, very scary."
How many of you guys have the brake switch adjusted to open as soon as
the pedal is moved down ever so slightly? I think this might be your
problem.
Originally, I think GE wanted the brake switch to act as a "kill the
tractor in a panic stop situation", not every time you just barely pushed
the pedal down. I kinda looked at it as the "wife's switch", as in when
she wanted to stop but still had her right foot on the speed control pedal
on my WH C-185.
This scenario is even more likely when applied to the large frame
tractors with the dash mounted speed control. In an emergency/panic like
situation, it's a lot easier (and more natural) to mash the brake pedal to
the floor than to reach for the speed control lever on the dash.
I may not remember our exact phone conversation all that well as it was
probably close to two years ago by now, but I think Steve Richardson had
his brake switch (on an E15 with dash mounted speed control) adjusted
"your" way because he never knew how it was supposed to be adjusted. Check
out Paragraph 1.15 BRAKE SWITCH ADJUSTMENT on page 1-24 of the Home
Owner's Service Manual.
I personally think the brake switch should still be adjusted to open
just before the brake pedal bottoms out on the footrest. Try it and I
think your hill problem will go away.
Mike in KY
----- Original Message -----
From: Ralph & Elaine Vogan
To: Archive, Elec-Trak
Sent: Thursday, February 23, 2006 12:59 PM
Subject: Re: (ET) Alltrax install!
David Roden (Akron OH USA) wrote:
I have that very diagram right here on my computer. If you need a copy, you
can download it from here :
http://www.alltraxinc.com/old/Manuals/DCX-ET%20Manual.zip
Thats the same one I have. My old eyes didn't notice the power bypassing
the main relay though the 1 ohm resistor
According to the diagram, those safety switches connect to the KSI
(keyswitch) input of the controller (6th pin from the left), not to the
main
contactor.
Yes, but turning off one of these switches should turn off the B+ to the
main contactor coil
Battery voltage on the KSI terminal enables driving current from the
controller.
Any time the main disconnect is on, battery + is also applied to the 8th
and
9th pins (designated logic B+ and B+ power respectively). These are
supplied from a tap *ahead* of the main contactor. The main contactor coil
is
powered by an output from the controller, not directly by the keyswitch.
I thought the main contactor was connected to B- through a timer in the
controller.
Those pins (8 & 9) are specifically intended to be powered *even when the
KSI terminal is not* so the controller can stop the tractor as quickly as
possible under the following circumstances -
1. the brake is applied
2. the keyswitch is shut off
3. the operator leaves the seat
It uses plug braking to do that. I have experienced this effect on my
tractor.
If I want it to stop quickly, I just turn off the key or touch the brake
pedal.
The braking effect is quite pronounced!
A while back several people (including me) wrote in about the brakes
grabbing when we tried to slow down a little bit. Now I see it is the
motor that is stopping us. I have a steep hill in back of my house with no
way to go around it. The tractor speeds up going down, and when I touch
the brake pedal I slow down for about a foot then the wheels lock up. The
tractor tears up the grass and will start sliding sideways, very scary.
If yours doesn't behave this way, either you didn't wire it according to
the
diagram, or plug braking has been disabled in your controller. I think you
can
disable plug braking with the PC control program if you want to, but it's
been
quite a while since I ran that program on mine, so I'm not sure.
I don't want to disable the plug braking on the seat and key switches,
but I need a finer control of the foot brake. Do you think putting the
brake switch in series with the throttle switch would allow the motor to
coast then I could control the level of braking with the pedal and brake
pads?
I may be wrong, but my understanding of plug braking is that it does not
actually apply reverse current. Rather it maintains the field current
while
short-circuiting (or nearly so) the armature. This stops the motor very
quickly. If I'm wrong about that, I certainly welcome correction of my
misapprehension from the designers of the Alltrax, the designers of any
other
plug-braking controller such as a Curtis, or those who have studied plug-
braking controller design.
I agree, but plugging means to turn yhe field on & off to control the rate
of braking. To bad our Alltrax doesn't work that way.
Ralph
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