Hello, Thanks for the info. I would really like to build the controller
myself even if it's with alot of help :) The OSMC Yahoo group has been
a great source of info and I'm basing most of my circuit on it. The nice
thing
is I dont need to reverse the motor since it's mounted to my trans. I'll
need alot
less fets to get the job done. Your right about the voltage, 36v will move
it but
I want to pull the front wheels. When I let the magic smoke out I'll be
investing
in higher voltage fets.
I'm not building this to have an electric car but to learn how to make one.
So far the
money hasn't been to bad. I've spent around 250 bucks and its been alot of
fun to think
about so even if it doesn't work it was still worth it. Besids Im sure It'll
sell on eBay :)

My next stop is evdl.org thanks for the help.

> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
> Of Martin K
> Sent: Monday, November 13, 2006 7:47 AM
> To: Microcontroller discussion list - Public.
> Subject: Re: [ee] Best way to control a large dc motor
>
>
> Sorry, I replied before reading your original question -
> The answer is that you should probably get one of the large Curtis
> controllers or one of Cafe Electric's Zilla controllers (with the wait
> time over 6 months probably)
> The Curtis controllers are designed for forklifts. They have many medium
> power MOSFETs in parallel. The Zilla controllers use large and powerful
> IGBT modules. The Curtis is the least expensive way to get going unless
> you want to use what they call a contactor controller in which your
> batteries are combined between series and parallel sets with which to
> vary the voltage that reaches the motor. Sometimes a high power resistor
> is also used so that you can have a smooth transition between changes.
> It's not the "cool" solution but if you're just running your beetle on
> 60 volts or some such, it should be ok. You aren't going to run your
> beetle on 36v are you? You won't be very happy.
> Check out evdl.org too. They would be able to provide much more
> specialized help than the piclist.
> The general consensus with everyone who asks about building their own
> 500A motor controller because it might be cheaper is that it won't be,
> not even close.
> If you want to build one and you have lots of time and money and you
> enjoy difficult challenges, it would be fun.
> --
> Martin K
>
> peteHVAC wrote:
> > I'm adapting a forklift motor to power my trusty 72 beetle.
> > So far the mechanical part has been easy. The motor is a 36V 90lb
> > monster and I'm guessing it can draw upwards of 500A. Controlling
> > this much power has me stumped. I have the SCR control board from
> > the forklift but no schematics. I have found a lot of sites selling
> > controllers but not too much info on doing it yourself and looking up
> > the components for the original controls hasn't turned up anything. If
> > anyone can steer me in the right direction I'd be very grateful.
> >
> > Thanks, Pete
> >
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