When I move one of the three axes of the unpowered MPCNC by hand, the LCD Display lights up short and the Ramps stepper driver fan starts moving. The faster I move, the more this happens. Must be a induced voltage from the steppers and I fear, this could damage the electronics somtimes. Has anyone else observed this behavior?
Don’t do that! This happens with all cnc machines, even the big ones, and 3d printers. You can fry the motor controllers doing this.
For a bit more about why, It’s because when you move it by hand your stepper motors act like generators sending electricity back up the wires to the control board.
It is safe to move each axis slowly since it will produce a lower voltage and current than the board is usually powered with. But if you move fast, or move multiple axis at the same time at a medium speed then it could produce a higher voltage than you want.
If I remember correctly stepper motors produce AC voltage, not DC like the ramps board runs on, which makes moving it fast even less desirable because some components might not like the reversing of polarity above a certain frequency.