At 1:01 PM -0700 10/2/02, Lee Hart wrote: >Were you using the extra silicon in the armature controller to do a >boost converter?
Yes. >If you have sufficient field control, you can just >connect the armature to the battery thru a big diode (and that diode is >already there as part of the MOSFETs). This gives you regen at higher >speeds, but not down to zero speed. It might be practical if we were running a lower voltage system or maybe a different motor. We are running 144V and ADC 9". I suspect that at the speeds required to do that even at full field, we end up with a very hot commutator :-) The ADC motors really start arcing around 160 to 170 volts on the commutator, even at relatively low current. I don't know exactly why, but it seems to be a wall that's hard to get past. > > Overall I decided that in the volumes we are doing, for the hobbyist > > market, a AC drive makes more sense. The incremental cost in silicon > > for AC drive is not that big anymore, and the benefits are numerous. > >I agree if you are making a "high feature" drive (one that totally >emulates an ICE, runs transmissionless, does regen to zero speed, etc). That was our goal. Everything except transmissionless. It was very important to me that it would feel and drive like an ICE while providing easily used regen down to near zero speed. That is my personal goal. I agree that there are many ways to do things and that sacrificing some of those features could make it much easier to build. A little work on the drivers part can make a large difference, but I really want a car I can give to a soccer mom and she won't think much odd about it. (other than the quiet :-) -Otmar- http://www.CafeElectric.com/ Zilla "Got Amps" Shirts now available online. http://www.evcl.com/914 My electric 914
