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'84 QT20, T1 powering itself off randomly.

Bobw

Diamond
Joined
Feb 8, 2005
Location
Hatch, NM Chile capital of the WORLD
Sunday I was indicating some crappy part in on the lathe, and it just powered off... The turret dropped and squished my indicator...

Powered it back on, and it powered off, then again, then again... Then it was fine, then it powered off again.... Then it was fine
for a few hours and then it did it one more time later on... Haven't needed it since...

When it did happen, nothing special was happening... No thunderstorms(that I saw), never dropped out in a cut.. If there was some funky
power surge it didn't effect any other machines or computers, or the TV... If there was a short power blip the TV is usually the
first to shut off.... I won't discount the power blip.. It is summer time, and there is a thunderstorm somewhere close almost constantly.

Anyways... My plan is to run her here again and see if it happens again.....

What I'm asking is if there is a common failure or common point(crappy relay?) that would make this happen? Before I start chasing power
wires and swapping breakers, all the while hoping to not dig deeper into the machine.
 
Powered it back on, and it powered off, then again, then again... Then it was fine, then it powered off again....

Exactly HOW did it power off? Did the machine trip the main breaker or did it act like someone pushed the off button on the control?
 
Exactly HOW did it power off? Did the machine trip the main breaker or did it act like someone pushed the off button on the control?

Just like somebody hit the "power off" button on the control... Nothing tripped... Hit the green button and it came right back up, then right back down, then up,
then down... Then it stayed on for a few hours, then down again, and right back up for a few hours, and then we all went home.
 
On my rotary phase converter, before I swapped the phases around, my QT10 would "power off" under heavy load. The problem was that the control power was coming from the manufactured leg and one of the regular legs. Once I moved the phases so that the control power was only hooked to the two normal legs it never did it again. I suppose that I could make some adjustments to my phase converter, but I really don't want to have the no load voltage way high.
 
Update,

The powering off issue only happened that one day, I haven't run the machine a whole lot since then, a little thing
here, a little thing there. Last week I ran her 3 days straight with no problems...

Weird.
 
My T1 did this a couple times in the past week. Anybody else ever see this? Bob did you ever find out what was causing it? Thanks.
 
Anybody else have any suggestions? This is happening to me now once or twice a day. I've checked power supply voltages, re-seated the power on ice-cube relay, tightened all the line connections into the machine. Still doing it occasionally. Only seems to be while in auto with a program running. What else should i check?

Where are you Bobw? Would love to know what happened to your machine after.
 
Make sure all the fans in the rack of boards for the control are running at full force.

Next I would swap power supplies for the control.
My experience starts with T/M-2 controls, and I have replaced several in those machines for the same problem.

P.S you do not have any location in your setup.

Bill
 
All the fans seem to be running fine. I did get the machine to shut down once by tapping the electrical cabinet, which seems to suggest a loose connection somewhere. I've wiggled all sorts of wires/connectors trying to find whats loose with no real luck. Machine hasn't shut down in the past 3-4 days. Maybe I improved the poor connection slightly while looking for it? I guess I will have to wait for it to show up again and look for it then.

Bob, looks like your back online now, any update on what happened to yours?
 
Im still struggling with this same problem on this machine shutting off couple times a week randomly. Anybody have any new ideas on possible things to check?
 
Im starting to think it might be shutting down from variations in my power source. Happened a couple times yesterday when single phase supply (before phase converter) was down to around 234v. Later that day it was 239-241 and the machine ran fine all day. According to manual the control will power off in high or low voltage. The machine should be able to handle -15% voltage, but maybe the circuit that detects it is a little off after 40 years.

I think the machine transformer is tapped for 240, im considering retapping for 230 to bump it up a little. But im a little nervous I might fry something. Bob, any chance you could measure your voltage at spindle drive? Ive gone through manuals and cant really see anywhere to confirm what it should be. It says I should have 100VAC going to control. I will check this as well. Thanks
 








 
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