Yet another magic controller dead!
Sorry Dave, I know how you feel.
Okay I replaced the fet's with 6 of these
IRFB3207Z
It didn't work actually, so something else was toasted. Those IRFB320's are rated for 170 amps.
Dave, if you want my honest opinion, I would just lay the magic controller to rest and don't waste any more money on it. If you spend money on expensive FET's and it still doesn't work, well that's good money that could go on a different controller!
Also try and consider how much power you can actually get into that motor before it fry's. It looks similar to Leslie's HBS 1000 w motor, so maybe he can advise you better about it's power capabilities! If it's similar to my conhismotor 1kw motor, then The phase wires and motor used to get very warm @ 48volts 22 amps! So that told me not to increase the watts. I may have got more voltage in, I don't know!
Dave I think you have a few solutions,
1 Buy a different (non magic controller) controller rated for your motor.
2 Buy one of the infinion controllers I bought, from ebikes.ca and one option would be to buy the 40 amp with the direct plug in cycle analyst, which will mean you can adjust the current until you find the best balance between power and what's safe for your motor! The cycle analyst takes a second or a little less to kick in the limit, but is not a problem IMO.
The controller can with a simple resistor change, go up to 84 volts. I think this option would be the cheapest option in the long run if ever you decide to get the external controller Magic Pie motor, or any other motor. You won't have to buy another controller!
Best of luck!
Mark