I need help designing a PWM Circuit. I want to build it to power an auger motor on my salting machine. The motor specs are 12v DC, 40amps, Stall Current 90amps, 1/2hp, and 1800RPM. Any help would be greatly appreciated I just need some direction to fit these parameters.

 

You can get 60amp controller on ebay for $8.50 fit a 65a fuse.
Max.

 

I did see those, Just wanted to build my own.

 

Go see PWM motor controller on Google.
http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm
Size the Mosfet accordingly.
Max.

 

Go see PWM motor controller on Google.
http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm
Size the Mosfet accordingly.
Max.

Am I right in thinking that a MOSFET large enough to comfortably handle that amperage will probably need a gate driver in order to avoid excess heat dissipation? Or is the 555 likely to be able sink/source current quickly enough to satisfy even a hungry MOSFET gate?

I guess most of the circuits I'm thinking of in which this was an issue were driven by microcontroller outputs, not 555s, so maybe that's the key difference?

 

The 555 should be capable of driving most Mosfets for this application, also if if the PWM frequency is kept as low as possible, it will help, not usually required to go above 5Khz - 8Khz.
See TI SLUA618 p2 - p4.
Max.

 

The 555 should be capable of driving most Mosfets for this application, also if if the PWM frequency is kept as low as possible, it will help, not usually required to go above 5Khz - 8Khz.
See TI SLUA618 p2 - p4.
Max.

Sweet, thanks!