Help, Mori shutting off on it's own!

[spock]

1985 or so, Mori Seiki Sl3H, Fanuc 10 TE control

A few months ago, it started doing this occaisionally, then stopped, then came back today with a vengance!

here it is: while running, the relay switch that allows voltage to the CRT and control panel, will "throw", and I cant figure out why. It can be in cycle, or not, spindle running, or not, pulling a load, or not. The relay clicks, the crt goes black, and the lathe stops whatever it's doing, and must be re-started.
There is a dial on the relay, that adjusts from something like 9 to 12 amps. We put a meter on it, and even when the machine is under load, it aint gonna get near that load on that relay. I did turn the dial up, and it didnt change anything. So, I have no idea what is causing this, all I know is the work is piling up and the repairman cant get here till late tomorrow. Any ideas???

[premier_industr]

My guess is the 24 volt power supply.

http://www.cnczone.com/forums/showthread.php?t=41086

[jaherrera3499]

That's right. Most likely its the 24V circuit. I have found that a bad or damaged chuck actuator open/closed limit switch causes a lot of shorts. Check them if you have them. Make sure no chips are back there and causing damage.

[underthetire]

Be prepared for a few days down time. Most likely the cable from the I/O to the turret. They flex back and forth and eventually break. Could be coolant in a switch somewhere. Start documenting it before the service guy gets there. Is it on the same tools, same x/Z position. Chuck clamped/unclamped etc. Also make sure the small cabinet is closed and locked. The switch for the control cabinet will cause this problem as well.

[underthetire]

Sorry, miss -read your post. I think what you are describing is a overload relay for a contactor. That is different then the Fanuc control relay. If you have to manually re-set it, and the amperage load is ok on it, you have a bad overload. They do fail on the old machines quite often. I've bought them at Grainger in the past. Mori will have them in Dallas as well. It would be cheaper for you in the long run to go ahead and order one overnight so the Mori rep can change it out if thats what it is. I think they are less than 100.00. A second service call to replace it would be way more. If you don't use it this time, you will soon enough.

PS, could be the contactor as well. I usually change the whole set when I do them if they are original.