OK, this topic has induced me to resubscribe to the EVDL, it's
probably been 20 years since I was officially signed up. I've
occasionally passed replies through several members (thanks Lee,
thanks David), but maybe it's time to get out in the open.
What you have there is similar to the shunt-wound motor in my
factory-conversion SCT Rabbit from 1981. I can't tell you anything
about the controller, but the motor is very familiar.
Shunt wound motors differ considerably from series wound motors. For
one thing, they have regenerative capabilities as a native behavior.
The field windings are energized separately from the armature (they
are also known as "separately excited" motors). I'll leave it to you,
or others to do the research on the technical principles involved,
but suffice it to say, the armature runs at 100% voltage (direct
connection to the batteries through a contactor), while the motor
speed is controlled by ~weakening~ the field voltage. That's right,
~weakening~!
You can not run this motor by simply applying a voltage and watching
it spin. There is a startup sequence, which consists of applying full
voltage to the field windings, and a current-limited (via resistors
or other current limiters) voltage to the armature. This causes the
armature to come up to an idle speed slowly (4-5 seconds), at which
time the controller applies full battery voltage to the armature.
These motors have poor stall torque, so it "idles" when not actually
driving the vehicle forward. Mine idles at about 1,800 RPM (120 volt
nominal battery supply). This is with full field. As the field is
weakened (by a PWM or "chopper" circuit), the motor speeds up.
This type of motor allows a fully functional "one pedal" driving
style. Step on the accelerator to speed up and let off to activate
*very* powerful regenerative braking. I see 200+ amperes while
downshifting through all gears (I realize that your vehicle is locked
in 2nd). Using the service brakes is not necessary except in an
emergency or to come to a complete stop.
Before you do anything else on this van, you MUST check a few things
beforehand.
On the end of the motor that you have pictured is a conical shroud
held on by clips/clasps. This is the brush end of the motor. There
are eight armature brushes under this shroud. If the van has been
siting for any length of time, you would be well advised to pull this
shroud and check to see that ~all~ of the brushes are free to slide
in their holders *and* that none of them are stuck to the armature.
also clean out any dirt/dust/cobwebs/insect or rodent nests you see!
Now, as for your test to see if it ran. Did you twist the key over to
the "start" position? Because the motor has a start sequence, there
must be some method of engaging the field voltage and armature
current limiting circuits. Installing a fresh 12 volt accessory
battery will likely be necessary, as the controller obviously
requires a low voltage supply in addition to the traction battery.
Until last week, I had a web site with extensive documentation on my
SCT Rabbit, including information on the motor, etc. Some of this may
be useful to you, so drop in to the archive.org Wayback Machine and
check some of the PDF files that got saved in a snapshot of my site
from seven or eight years ago:
http://web.archive.org/web/20111109054159/http://www.mrsharkey.com/SCT/index.html
Glad to answer and questions you have, sorry to be completely
ignorant about your controller.
____________________________________________________________
1 Cup (Before Bed) Burns Belly Fat Like Crazy!
worldhealthlabs.com
http://thirdpartyoffers.juno.com/TGL3131/5ce8c08fdf8e640876987st04duc
_______________________________________________
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)
