(ET) Alltrax regen brake / roll-detect feature

["Markus Lorch" <mlorch vt edu>]

Hi all,

I've read about these regen brake and roll-detect features of the
alltrax and I have two questions:

1. I thought the regen brake is more a plug brake. I.e. they shorten
the armature with the field applied. I didn't have the impression that
they actually increase the field strength to slow down the tractor.
Or do they do that?

2. When do they activate they field. It seems that for a brake and
roll-detect
function they have to have the field powered at all times. It this the 
case?

I have bought myself also an alltrax, but for price reasons I have chosen a
model without the field control. My main motivation is to get rid of the
starting resistors in my E20 AA (for those of you who have seen how I
mounted
my front winch you know why :). The other reasons is that I want to have
more
power in slow speeds, have a over-current limit (my FW override circuit is
bad),
and I want to be able to gather power usage data via the serial interface. 

Initially I will leave the 4 main F/R contactors and switch direction this
way.
I will also leave the field weakening resistors in place. I don't think I
can 
continue to power the field from the armature leads with  the four diodes 
on

card 4 as the power signal on the armature will be pulsed and would lead 
to 
a reduced field strength. I am thus thinking of turning on the motor field
with 
the key switch or whenever either the accellerator or brake is depressed. 
What do you guys think? How would you do it?

Markus