around. The controller (as tested) is designed to easily drive
a 50 amp motor. By adding an additional four FETs, we can
crank that up to over 100 amps.
Well, I’ve taken you through some of the steps in
bringing a motor controller to life and some of the software
issues involved in making it go. For space and time reasons,
I’ve left out a lot of details. Other roboteers have told me
they are not always concerned with lots of details, but more
interested in the overall process of bringing a design to life.
It’s in that vein that I wrote this article.
I hope you have seen that it’s not easy to successfully
and safely do this when you get above a certain power
level. It requires a lot more attention to details.
I like to stress that if you try and build something like
this, make sure you apply the proper precautions and
safety factors. I can’t say this enough times. And remember,
and no rings or jewelry when working on power equipment
— gold melts quite easily. The unexpected happens and with
a 24V supply at 50 amps, that’s 1,200 watts that has to
go somewhere ...
Time allowing, we will try and do a follow-up article
with some additional real life testing: stall tests, temperature
tests, and perhaps a destruct test. We would also like to try
the controller with four additional FETs. NV
November 2006 21