I have an old treadmill motor:
Permanent Magnet DC Motor
Electrical Rating: @130vdc 2.5hp 6700rpm 18amps
Continuous Duty @95vdc 1.5 hp
I need a speed controlled drive circuit for it. I didn't want to spend $60-$100 on what seemed like a pretty trivial task. Create a PWM signal, run it through a MOSFET driver, drive my higher voltage with this MOSFET and thus PWM ~90vdc to my motor and control it's speed via a POT.
Well in theory it all worked. I polled a POT from my Netduino, giving me control of a PWM output signal. I fed this signal to a MOSFET Driver IC (tc4452), which would in turn drive my MOSFET(s). The MOSFET(s) would thus be switching the higher voltage.
Tested it out with a lamp(no scope at home) so I could see if I was on the right track, and it dimmed and brightened (thus modulated the 90vdc) just as expected. However, it did not run my motor. I hooked it all up, everything was cool until I started moving the POT higher and the motor started reacting and then FIREWORKS! My MOSFET was toast. I tried placing 2 parallel thinking it could possibly be too much current and this might divide it, but no dice. More fireworks! :) I always wear my safety gear when toying with this kind of energy though, so no worries. Just frustrating.
So rather than wasting anymore components I would like to ask some expert opinions on the matter. Are my FETs just not beefy enough for this? or is there a possibility that the FET driver isn't actually saturating the FET properly? I would like to hear any opinions really. I just don't wish to waste money on beefier FETS if I'm just not driving the type I have with enough juice, or if I'm just overlooking something really stupid.
Thanks a ton!