This question refers to a non-road EV, but I think it's applicable to road
EVs too.
I recently bought an Alltrax controller for my Elec-trac tractor. Like most
(all?) DC controllers, it has 3 high power terminals. In this case they're
B-, M-, and B+M+ (actually marked just B+ but described as the B+M+
terminal).
The printed manual with it contains the following intriguing warning. It's
printed in boldface type and underlined text (in parentheses, quotated,
capital letters ... no, wait, that's something else).
"Connect the motor leads as shown, making sure that you connect the B+ power
lead from the contactor and the A1 motor lead AT the B+ terminal of the
controller. This is important for proper controller operation."
I read this as meaning that I should NOT, say, run a single cable from the
contactor "downstream" side to the controller B+M+ terminal, and then
connect the motor A1 lead to the contactor at that "downstream" terminal.
Instead, the motor A1 lead should be extended to the controller B+M+
terminal, so that there are 2 lugs on that controller terminal.
View following with a monospaced font such as Courier:
RIGHT:
|---------------------
| |
| Motor
B- |M- B+M+ |
|---------() -() ()--------------
- |
--- |
- |
--- |
|___________________|
Battery Controller Motor
WRONG:
|---------------------
| |
| Motor
B- |M- B+M+ |
|---------() -() () |
- | |
--- | |
- | |
--- | |
|___________________|______________|
Battery Controller Motor
I've previously connected DC controllers the "wrong" way -- that is,
connecting the motor lead to the contactor when it made for a shorter motor
lead. It seemed to work fine.
I guess my ignorance is showing here. Can someone explain why connecting
the motor directly to the common controller terminal, not some other
terminal feeding it, would be "important for proper controller operation"?
David Roden - Akron, Ohio, USA
EVDL Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" and "etpost" addresses will not
reach me. To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
