The variable frequency drive (VFD) released it’s blue magic smoke in spectacular fashion this evening during a metalshop authorization class.
A new one is on order and should be here early next week.
I think some dust got into the top of the VFD (i had just wiped it down after a pile of soot had built up on it). So when it shows up, i’m probably going to design a snorkle and filter for it to help protect the unit… and also add a downtube for the disc sander that was aimed directly at the VFD…
I see people operating the grinder by turning the motor on and off but leaving the vfd on. In general vfd do not like to have a load applied or removed like that. The motor should be started and stopped by using the start/stop buttons on the vfd itself.
If i have the time and energy, i may end up removing that top power box altogether, leaving only the buttons below (kinda hard to leave running that way)
Can we wire in a switch to the low voltage input so the user can still flip a switch to start and stop the motor, but the vfd won’t get unhappy? In fact, maybe the top box can be wired to do that instead of feeding the motor.
My understanding is the fets let go when the vfd fails. I wonder if it would be something one of the folks in @Electronics would want to look at
Yes, please keep the bad VFD in case it turns out to be repairable for a spare at a reasonable cost. And yes, it might be possible to rewire it to use the upper on-off buttons as a VFD run/stop input, if that is considered useful, but I’d have to look at the switch internals before making any promises. I think I would vote for VFD front panel controls only, under the ‘keep it simple’ system, but I’ll wire it however everyone wants it, if it can be done.
Generally, even the cheapest VFDs on amazon have external inputs for both the speed, direction, and start/stop. I don’t recall the model so I can’t pull up the manual.