On Sun, May 25, 2008 at 02:15:40PM -0400, Djula Djarmati wrote:
> > 3) Still searching for good availably and price. WarP 9's have 6 week or
> > more lead times and run in the $1700 to $1800 ballpark.
> >
> > That leaves the electronics. From both a cost and integration standpoint
> > there's a lot to be left desired with control electronics. The major
> > subsystems:
> >
> > 1) PWM motor controller. Not a fundamentally complicated piece of
> > equipment. Accepts a limited number of control inputs (5k throttle pot,
> > brake switch) and controls via PWM a high powered switch between the
> > battery bank and the motor. An example is the Curtis 1231C controller:
> >
> > http://www.electricvehiclesusa.com/product_p/co-1231c-8601.htm
> >
> > I'm almost ready to choke on the $1400 price tag.
> 
> Before doing the electronics all by yourself, I would try FANUC CNC
> spindle motors and controllers like these:
> 
> http://cgi.ebay.com/Fanuc-spindle-motor-a06b-0759-b970_W0QQitemZ180243520740
> (30kW at 40%ED, 22kW continuous)
> http://cgi.ebay.com/FANUC-DC-SPINDLE-SERVO-DRIVE-MODEL-SP12_W0QQitemZ220237949247
> (I don't know if this one fits the motor, it's just an example)
> 
> These motors and controllers are very rugged, protected from overload,
> short circuit, etc. and you also get regenerative braking since they
> brake by dumping energy to DC rail. The controller keeps the set rpm
> automatically and goes in reverse.
> 
> The only drawback is they expect 200V 3-phase which is around 300V on DC
> rail. The price for these starts at $1000 for each item.

Which makes it a non starter. Used EV controllers can be had for about 1/2
that price.

My point is that the component costs are only about 15 percent of the
retail price of these controllers. Paying $1400, or even $1000, doesn't
make a lot of sense when the parts can be assembled for $150.

> If you make it work, you can experiment in making your own by looking
> the way FANUC did it. If you go this way, let me know and I can find
> some datasheets.

As I stated in my original post, nothing about any of the technology is too
particularly complex. The controller is little more than a PIC driving a
IGBT driver which drives the IGBT with a PWM signal. The input comes from a
standard 5k throttle pot going right into the ADC input of the PIC.

The battery charger, for lead acid, again is little more than taking full
wave rectified DC and buck regulating to thre required voltage. Same for
the DC to DC converter.

I'm really just wanting to make sure I don't miss a crucial design
component. And looking for suggestions on some of these high power
components, such as inductors and ultra fast recovery diodes.

BAJ
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