LinuxCNC power failure protection

Hi all,

I am starting on a retrofit on my first CNC machine here shortly. I'm planning on using LinuxCNC for the machine. My location has 3 phase power from the power company, but I am literally the end of the line for the branch circuit that feeds me. I often have power disturbance issues where the power will flicker out for a second and then come back, sometimes just on 1 leg, other times all three. Yesterday it was bad enough that my manual lathe actually had the motor contactor drop out.

I had an idea to combat this somewhat for my CNC conversion.. Has anyone put a battery-backed power backup on their linuxCNC computer, then wired 3 relays to the incoming power legs, with their contacts in the E-Stop loop? My thought is that way, when the power flickers for a second, the control PC and mesa cards would stay powered on, and the machine would stop and stay stopped until manually restarted.

Thoughts?

I dont think a mains battery bank will work as this machine has a 60hp spindle and 6hp servo motors. Its a CNC boring mill.

I believe I will investigate this more.

I'd probably be money ahead to just run the machine off of a propane genset.

deerefanatic wrote:

I'd probably be money ahead to just run the machine off of a propane genset.

A 24 volt DC 3 phase contactor with a UPS protecting the PC and the Mesa power should do exactly what you want. If the mains power trips, the contactor will need to be reset but the control side will remain powered up by the UPS for safety. This will mean when the power is restored, nothing will start automatically.

It might be better to use a safety relay in the mix as well.

I would suggest adding a means to monitor the voltage drop out, so that when the voltage drop occurs the current XYZABC etc axis positions and gcode line are recorded (saved to a file) so that the machine could be restarted from that position.

3D printers with Marlin firmware use / have that feature available.