When the Nomad 883 Pro is turned off, and I move an axis by hand, the spinning of the motors seems to cause the power LED to glow.
I suspect the stepper drivers have flyback diodes that are dissipating the charge back into the power supply, so I am guessing the driver chip’s transistors are not damaged. But without a schematic, I can’t be sure of anything. I am hoping that the maximum amount of power that leaks back is taken into account and won’t damage anything.
If it helps you understand my concern, my 3D printer has also has a small issue with a capacitor retaining charge for too long, as in, you can unplug it, and turn on the switch, and it will actually power up for a split second. Forgetting this during hacking/maintenance is dangerous, perhaps not to the human, but that stored charge might get shorted into something that can’t handle it.
So my next fear is for safety. I’m moving things around while the machine is off, because I am trying to avoid pinching hazard or a rouge spindle. I am not sure how the power switch works on the Pro version of Nomad but if it’s a relay, I don’t want it to latch up accidentally, and then have the machine receive a misinterpreted packet that makes it go crazy.
Trust me, it’s happened on other things before. I’ve had my hand cut up because a quadcopter interpreted a electrical glitch as a command to go full throttle. I don’t think GCODE has checksums to ensure this doesn’t happen.
Questions:
Is moving the steppers by hand damaging the machine’s circuitry?
Is the circuitry designed in a way that will prevent a unwanted startup?