Big laser update

TLDR - Don’t use or mess with big laser. We have a ground fault and other potential issues. Could be dangerous (not likely, but this machine has many many many lethal voltages and currents – small probability is not small enough).

I came in this morning and checked out the electrical systems in the large laser:


  • Alarm wire is properly connected from chiller to laser

  • Laser high voltage power supply shuts off if chiller is off.

  • HV power supply seems okay.

  • The GFCI is working.


  • The GFCI is tripping

  • We have a ground fault / leakage currents.

  • This is potentially very dangerous.

  • Alarm circuit is only partially wired. It will work this way, but we should be using both alarm signals, as this prevents a condition in which the output could “stick” or remain “open” even if there is a fault.
    I suggest finding the electrical faults before doing anything else. We should obtain a proper leakage tester (a cheap china one is fine), and figure out what is causing the problem (could be chiller, buss, multiple power supplies, blower, bad capacitors, degraded insulation, mains wiring, etc). I’ll add one to the warden’s list. I’d like to rule out the destructive and dangerous possibilities.

Once again, in high voltage equipment, this sort of fault is often caused by dust, grime, fumes, inadequate circulation, insulation breakdown (which dust, fumes, and grime accelerate). So, hopefully, this is the only issue, and cleaning and tightening everything will prevent future problems. If there is a major fault, we need to find it before proceding.