Sounds to me like what was actually used on the 1995 Tropica?
Peter Crisitello [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lee Hart Sent: Thursday, February 07, 2013 1:54 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Series and parallel switching 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) _______________________________________________ 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)
