Enco lathe won't turn off.

[trainman2]

Yes if there is are two relays. one for forward one for reverse..!

There are there are two contactors and one small relay. The pick coil on the

My money is on a sticking apron switch- they seem to be prone to fail after long use more so than the contactors

I might note this problem was there when the machine was NEW out of the crate. Would you know if the switch comes apart, to clean or burnish the contacts?
I have a spare contactor which I am thinking of swapping out. I would also like to replace the small relay what I call control relay. Any suggestions on where to purchase one. It is labeled OMRON MY2. See attachment.

 

[tq60]

Those omron are very common

Amazon has many options.

About 5 bucks or so each.


Contacts do seem to more common to not make good contact on them.

We have about 10 in a controller and maye 3 had flaky "MAKE" contacts.

Sent from my SM-G781V using Tapatalk

 

[trainman2]

Yes if there is are two relays. one for forward one for reverse..!

There are there are two contactors and one small relay. The pick coil on the

Think of it like a single pull double throw switch, it can get stuck in one position but works fine in the other, if there are two relays. one for forward one for reverse it can happen..! My Emco 12x36 had 3 relays...

From what you describe a bad relay is my hunch, but without being there to view and test, I can only try to give you optional places to check... your Emergency switch sounds like it kills power to a low voltage relay that energizes a high power relay, when you hit the switch it de-energizes the low power relay, but if the high power relay is stuck closed it will still supply power to the motor, Not a true kill switch.

does the power light go off when you hit emergency stop...?

Hope you find the issue and report back your success.


View attachment 440261

There is no light, might be a good idea to add one. I am thinking of swapping out the forward contactor with a spare I have and replacing the low voltage relay. Any idea where I could get one. See attachment.

 

[mksj]

You should not need to replace the small relay, it is an interlock style that locks on when the machine is turned on and in the stop mode, and handle minimal current (just that of the contactor coils). The small relay is usually DC and have a small rectifier to the coil. It should drop out when the E-Stop is pressed, and only reset when the spindle switch is in the stop position.

 

[trainman2]

You should not need to replace the small relay, it is an interlock style that locks on when the machine is turned on and in the stop mode, and handle minimal current (just that of the contactor coils). The small relay is usually DC and have a small rectifier to the coil. It should drop out when the E-Stop is pressed, and only reset when the spindle switch is in the stop position.

If it is tacking would keep the lathe from stopping?

 

[trainman2]

If it is tacking would keep the lathe from stopping?

Also are there two coils on the contactor? pick/hold

 

[markba633csi]

Only one coil on each contactor. The purpose of the small relay is to prevent the motor from starting until the apron lever is in the stop position first.
That pulls and latches the little relay and then when the lever is moved up or down the forward or reverse contactor will pull in.
After re-reading your first post I realized the problem must be a sticking contactor, not the apron switch, although apron switches do fail after long use.

 

[RJSakowski]

Thirteen years ago, I bought an Enco horizontal band saw for our small startup. The switch was wired so that the power could not be tuyrned off. I rewired the switch correctly and everything was fine. I contacted Enco and they apologized and offered me a gift certificate for my next purchase.

It sounds like the guy that wired the band saw also wired your lathe.

Since the problem has been around since the lathe was new. I wouldn't suspect a stick relay. Also, a stick relay is usually due to contacts welding and would be inoperative in any circumstance. OTOH, failure to make contact can be due to burned or oxidized contacts and the relay may partially function. For example, contacts on the other side of a double pole relay or the remainder of multiple relays may still function.

I would suggest using the schematic diagram, tracing out the wiring to look for mis-wiring.

Oh, bu the way, the saw was actually branded as MSC.

 

[trainman2]

Only one coil on each contactor. The purpose of the small relay is to prevent the motor from starting until the apron lever is in the stop position first.
That pulls and latches the little relay and then when the lever is moved up or down the forward or reverse contactor will pull in.
After re-reading your first post I realized the problem must be a sticking contactor, not the apron switch, although apron switches do fail after long use.

Thanks I am going to start with the contactor.

 

[jbobb1]

There's no doubt the forward micro switch isn't sticking. I have a Jet lathe that had a similar issue.