sndscientist
- Jul 10, 2013
- 47
- Joined
- Jul 10, 2013
- Messages
- 47
ok for a project i am currently working on i recently built a nice simple pwm circuit for controlling a rather hefty dc motor. the motor is rated at 18 amps at 130vdc. 1.5 rated hp. i am not going to be running it at 130 volts rather 36 to 48 volts (haven't decided yet). I have the PWM and snubber circuits already built to protect my output fets from the lightning storm the collapsing field will generate. also have a neon light across the motor for good measure to help the over 70v clamping. my question is what fets do you suppose i should use? my last 2 pwms i built i used the irf610's and the irf 540s. this one i started using the irfz48vs because of the pulse drain current of 290 amps where as the 640's have a pulsed drain current of 72 amps and the 540s at 110 amps. my concern rises mostly because the irf48v bank gets abnormally hot on a simple test using a smaller 3 amp 12 volt motor. much hotter than a single 640 with a tiny heat sink got on a 12 volt 30 amp motor.