how hot is too hot?

Yeah, that's a bit too hot. On my truck I have an electric radiator fan ducted to the motor endbell that blows air through it continually. Helps a lot! Not sure what kind of fan you could use for a motor that size, though.

And just for kicks, how about water cooling? Wrap some copper pipe around the motor, and circulate water through a radiator. Ya never know.

Awesome machine, BTW. Just out of curiosity, did those contactors come out of a forklift? I have a few just like that from a lift...

I have considered a fan and water cooling, just haven't found a good way to fan cool the motor.
Contractors came from ebay, think they were from solar arrays.
I would like to nip the heat problem in the bud so I don't have to reinsulate and rewind the fields.



http://www.austinev.org/evalbum/preview.php?vid=1174

Yeah, looking at your motor it looks like it would be hard to duct air into it. My motor has a relatively "open" endbell that makes it really easy.

Maybe take a whole bunch of little CPU fans and attach them around that vent on the end, blowing air through it?

One thing about these motors is they don't like to be run at low RPM... so if you're running a direct drive setup, with a lot of stop-and-go, that's not going to be good for the motor in general. If you increased the gear ratio a little it might help.

I had to rewind the fields on my motor once. What a pain, huh?

Trying to figure out why you are getting the motor so hot.

My 1st 48 volt system had only a 5hp motor pulling a 1600 pound car, 15 miles @ 40 mph and the motor didn't get overly hot.

What is your motor rated at for continuous duty?

The continuous rating is 80 amps, I thought it would tolerate intermittent overcurrent, if I keep the controller limited to about half it is fine. I am trying to work with what I have, I may have to just bite the bullet and buy a larger motor to get the performance I want.