On Tue, Jun 30, 2009 at 01:49:01PM -0400, Chris Loper wrote:
> Thanks for the replies. 
> Please pardon the slowness of my response 
> as I get the piclist in the digest form.
> 
> >From Dwayne and Chance, it seems that I will not 
> likely do better than the $75 Hbridge on eBay
> (even if I build it myself).
> 
> Thanks to Olin, Dwayne and Martin K., 
> I realize that my assumption that I need an Hbridge is wrong.
> If I decide to pursue the relay / mosefet option, 
> can anyone venture a guess on how the cost 
> for the relays, mosfets, etc might compare 
> to the $75 mark set by the eBay Hbridge?
> 
> I've found a lot of good information here
>    http://buggies.builtforfun.co.uk
> I'll be researching for a while.
> Thanks again.
> --Chris
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I've built a PWM driver for a go-kart around this size (1.3kW stalled)

   http://dspace.mit.edu/bitstream/handle/1721.1/33705/64667085.pdf?sequence=1

See Section 5.1 page 43. (and page 39 for the shoot-through delay
circuit)

You can do without the output filter --- we just had that to have the
students practice inductor design.

Also I don't say it in the writeup, but you need need good heat-sinks
on the FETS.

-Mar.
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