On 2/5/2013 10:11 PM, Ds2inc wrote:
Ideally yes the two motors. The goal is a 2 speed elec transmission
Without the Zilla and hairball. I'm running two pm motors with the
following, in a front wheel drive Saturn sl1 using 4-1 differentials
gear reduction on each motor vs the auto trans.
MOTOR SPEC DATA: 97V 9 HP WITH 5,700 RPM
72V 6 3/4 HP WITH 4,200 RPM
60V 5 3/4 HP WITH 3,500 RPM
48V 4 1/2 HP WITH 2,700 RPM
36V 3 HP WITH 2,000 RPM
24V 1 1/4 HP WITH 1,100 RPM
UP TO 21HP INTERMITTENT...
Sounds like an interesting approach.
The Zilla uses contactors to switch the between series/parallel (and
forwqard/reverse). It has logic to watch the contactors, and decide when
to switch for you. You would have to provide the equivalent of this in
your controller. The manual is online; you can look at the contactor
setup and see how it's done.
Basically, you wire up a set of contactors (or big switches) to do the
series/parallel switching. You will also need reversing contactors,
since you don't have a transmission with your setup. Finally, you need a
main contactor, to shut it off in case the controller goes berserk.
Depending on your wiring, there may be circumstances where it is
dangerous to turn on one contactor before another one turns off. The
Zilla setup uses contactors with auxiliary switches, so the hairball
*knows* whether a contactor has switched or not. For your setup, you'll
want to include something similar.
PM motors run at a speed controlled by the voltage. If you run them in
series, the current (torque) in each motor is the same, and the voltage
(speed) will self-adjust; they act like a standard differential.
If you run PM motors in parallel, their voltage is the same, and they
both run at the same speed. They behave like a limited-slip or locking
differential. Nice in snow or on a drag strip; but it leads to extra
losses in normal driving. Going around a curve, the outside motor is
forced to turn faster, so it becomes a generator, and is actually
dragging the wheel backward (negative torque). The current it generates
drives the inside motor harder, trying to make it turn faster.
--
A truly excellent politician will tell you everything you want to hear.
A truly excellent engineer will tell you the truth. -- D.C. Weber
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
For EV drag racing discussion, please use NEDRA
(http://groups.yahoo.com/group/NEDRA)
