On 12/25/2012 8:54 AM, Robert wrote:
Personally I don't think it's a good idea to over voltage DC motors especially when they are loaded as the extra current can burn out the fields and armatures. It's easy enough to PWM hi efficiency 'H' bridges to reduce the voltage very efficiently. I like the HIP4081, it's an old chip but I've had very good success with it. (it doesn't hurt that I have a bunch of them either!) I may even use it to control the main drive motor.
True, the thing I'm wondering: Is it better to raise the voltage so it doesn't stall the commutator (which kind of happens on 18 volts). It most definitely does *not* stall at 30, and I use the front life very intermittently so it shouldn't overheat.
Tiller motor is a different story; I use that a *lot* and although it bogs down a lot it doesn't quite stall. But I may try it this spring on 24 volts.
I haven't built a controller, but I do repair the US Electricar 50kw AC induction controllers. Which gives me a small supply of 1/2 blown 600a igbts to practice with.
Chris