This mosfet power board will produce up to 40amps 12v-100v dc. This would handle greater amps with good heat sink and greater gage wire on mosfets.

Most pwm will work well with the right resisters on gate input. MOSFETs are well known to be prone to inexplicable failures - to the effect that the alternative expansion of the MOSFET acronym is 'Magically Obliterated, Smoke and Fire Emitting Transistor'. The truth is that MOSFETs are incredibly robust - but that they fail very fast indeed if any of their rating are exceeded. There are a few ratings which are very difficult to get sensible information on, and which can cause problems. This page (which can never be complete) is a start on trying to explain some of these.

Yes - if you put too much current through a MOSFET - it will fail. Exactly how it fails will depend on how high the excess current is and for how long it flows and on the exact circumstances at the time.

If the load is short-circuited, the current will rise . However - we do not guarantee the controllers are safe against short circuits, for if the short is sustained and is 'too short' - failure can eventually occur.