What was the resolution, replacing the contactor?
-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Enco lathe won't turn off.
- Thread starter trainman2
- Start date
- Joined
- Dec 14, 2018
- Messages
- 629
The forward micro switch would constantly stick. This being an older machine and other things were going wrong, I stripped the all the contactors and switches and upgraded to a VFD. Was the best choice I could have made.
What is a VFD? I made the problem worse today. I swapped the forward contactor with a spare I had, and the lathe would not start forward or reverse. Swapped the old one back still no forward or reverse. Started checking voltages and see power on the hot side of the contactors. But no low voltage on the transformer. The winding does not seem to be open and there is input voltage. Not sure where to go....
I believe the contactor was the problem. I tried to test this morning and initialy could not get it to fail. I let the maching run for a while and it started failing. I turned to power off from the breaker panel and could hear the contactor drop out but upon resroring power the motor started. . Did it again this time checking the contactor befor turning the power back on and foung the contactor was still picked. Pulled it out with a pair of pliers restored power and was back to square one.
At this point it seemed the contactor was mechanically sticking so I decided to swap it out.
Last edited:
That is the bad one I took the cover off so I could pull the contactor out.
Thanks, I don't think I am up to a conversion like that maybe in my younger days. I was able to fix (I hope) the nonstop problem. I had swapped out the contactor and the machine would not start in forward or reverse. Swapped the old one back still no good. Started looking and realized a wire was on a spare lug with nothing on the load side. Looking at my pictures and notes the wire should have been on the adjacent lug.
It seems to be working now wait and see. The original problem was somewhat intermittent, it would go away for days at a time. I have to take the old contactor apart to see if I can find where/how it was getting stuck, Hope to find a rub mark or something. Thank all
It seems to be working now wait and see. The original problem was somewhat intermittent, it would go away for days at a time. I have to take the old contactor apart to see if I can find where/how it was getting stuck, Hope to find a rub mark or something. Thank all
- Joined
- Jan 2, 2019
- Messages
- 6,538
If you had started the VFD conversion when you started this thread it would probably be done now. Both my lathes have 3 phase motors with
VFD's and there's no way I'd ever go back. Check threads by @mksj for really good conversions, it's much simplier if you just use the VFD's contols but not really hard to wire in the original switches.
I have an identical lathe to yours and I think I spent around $300 to convert it. So happy to not be troubleshooting the original controls cabinet which you can have for the price of shipping.
Cheers,
John
My lathe did a similar thing a while back - turned out a thin layer of oil had found it's way into the contactor between the pole faces, on closing the oil kept the pole faces together by 'suction' - technically not really suction but with the air squeezed out from between the pole faces air pressure kept the contactor closed for anything up to 4 or 5 seconds, I figure that over the years the pole faces had become polished from being hammered together - all it took was a thin coating of oil to keep the contactor closed, cleaned it off with paper towel and it was all good.