Help please.

[tevans9129]

My 47 year old Rockwell 10x24 lathe has come down with a virus and I am hoping someone will have some ideas.

It runs great in reverse but not at all in forward. It has a 24 volt control system and the solenoid is not operating when in forward orientation. I have checked the barrel type switch and it seems to be OK but I have no idea how to check the solenoid. All wiring seems to be tight and I cannot see any signs of damage anywhere.

I am hoping that it will be a simple fix. Thanks for any suggestions.

 

[stevehuckss396]

Check the voltage on the control coil of the contactor. There will be 2 terminals below the top 8 terminals. With the switch in forward you should have voltage at the terminals. If you do and the contactor isn't clicking in you probably have a bad coil.

 

[ShopShoe]

A wiring diagram would be helpful.

Lacking that, What tells the control system that you are in forward instead of reverse operation?

Look for additional switches activated when you operate more than the barrell switch.

Does the solenoid operate in reverse operation? If the solenoid does not operate at all, check the coil for continuity (with the power disconnected entirely.)

--ShopShoe

 

[tevans9129]

Check the voltage on the control coil of the contactor. There will be 2 terminals below the top 8 terminals. With the switch in forward, you should have voltage at the terminals. If you do and the contactor isn't clicking in you probably have a bad coil.

Hi Steve, thanks for the suggestion, I will check that when I get back to the shop. However, there is a wrinkle now. I went to the shop earlier to take some measurements on the barrel switch and when I first turned the switch to "forward" I heard the solenoid operate, tried the "reverse" and it operated also but then the forward failed after that. Could this be a problem with the overload protection?

 

[tevans9129]

A wiring diagram would be helpful.

Lacking that, What tells the control system that you are in forward instead of reverse operation?

Look for additional switches activated when you operate more than the barrell switch.

Does the solenoid operate in reverse operation? If the solenoid does not operate at all, check the coil for continuity (with the power disconnected entirely.)

--ShopShoe

Thanks for the suggestions Shop, and yes the solenoid operates every time in "reverse" just not in "forward". The F/R is controlled by the barrel switch.

 

[tevans9129]

Here is the wiring diagram if it helps. There is one difference that I am aware of and that is there are 3 of the numbers 4&5 and there is a reset button on one of them.

 

[stevehuckss396]

When you say "it operated" does that mean the contactor clicked in and the motor spun, or did you just hear the contactor click in?

 

[tevans9129]

When you say "it operated" does that mean the contactor clicked in and the motor spun, or did you just hear the contactor click in?

The 220v to the motor is disconnected so I am only hearing the "click" when the switch is operated. It was the same when the 220v was connected, the lathe would run in reverse but not in forward and there was no click from the contactor when the switch was moved to forward.

 

[stevehuckss396]

Couple thing

Checking voltage you need to check these points to the other side of the transformer. That is the brown wires on the transformer. If you go from the wire on the switch to the brown wire on the transformer and get nothing, try the other brown. If you get 24v then you have found the proper brown and check everything to that brown.



The drum switch could be worn out and making intermittent contact. Need to check the voltage at the switch on the contact that goes to the contactor coil when the failure is occuring. If you have voltage

Check the voltage at the coil of the contactor. If no voltage there you may have a bad connection. Wiggle the wires to see if there is an intermittent connection. Tight screws doesn't always mean good connection. This also applies to the wiring after the coil. Bad connections can be where the wire is crimped in the terminals. If improperly crimped with the wrong tool they can be loose. With the power off pull on the wire at the connectors and make sure they won't pull out.

I you have voltage at the coil you could have a bad coil. I doubt that because it sometimes works. If the contactor is badly worn it could be hanging up mechanically and unable to pull in. Shut off all power in see if you can push it in manually and it moves smoothly and freely in and out.

Check all this stuff and see if you find anything. It's hard to help when your not standing in front of the lathe.

 

[Chiptosser]

As mentioned, check the contact surfaces on the barrel switch, also check the contacts on the forward contactor. The contact surfaces on the switch and the contacts themselves erode with use.

 

[tevans9129]

Thanks to all for the help and suggestions with my lathe. I went to the shop last night to start checking the suggestions and decided I would take measurements at the contacts of the switch first. First, they were measured and recorded with the switch in the OFF position, then I did the same with it in the REVERSE position. The voltages looked reasonable to me but was anxious to see how they looked in the ON position.

Glory be, I heard the contactor switch operate. I exercised it several times and it worked flawlessly. I have no idea what changed, just hope it continues to work.

I had previously checked the wiring and the switch contacts and had even cleaned the contacts but that had not helped then.

I have been using the lathe for a couple of hours this evening and everything has been smooth. Who says prayer does not work?

Again, I really appreciate all of the friendly suggestions and offers of help, much appreciated.

 

[RM-MN]

Have you been applying contact grease to the contacts on the drum switch? That grease will probably double the lifespan of the contacts.

 

[tevans9129]

Have you been applying contact grease to the contacts on the drum switch? That grease will probably double the lifespan of the contacts.

No, I have not...thanks for the suggestion.

 

[ShopShoe]

Intermittent problems are the worst.

In many cases you just end up waiting for something to completely fail in order to find out the real problem.

If the problem reoccurs, here are some other things to check:

RM-MN (above) beat me to the thought, but I was going to suggest inspecting and cleaning contacts in the drum switch and on the contractor.

I also second the thought about ckecking for a reason why the mechanism in the contactor might be hanging up.

Is there also the possibly that the detents in the drum switch are worn so it does not stop at the intended degree of rotation where the contacts are correctly engaged?

Best of Luck to you,

--ShopShoe

 

[ignator]

No, I have not...thanks for the suggestion.

I've had issues with dielectric grease on switch contacts, it will dry out and prevent switch closure. I recommend a product called DeoxIT. I use that for all switch contacts, as well USB sliding contacts and such. The smallest vial will last forever.
I had to replace a two pole switch on a Delta brand wood shaper. 240volt, and it would not break through the wax left after the oils evaporated. It was seldom used. I purchased a replacement for the switch, and tore the other one apart to see why it failed. I had used it twice in the previous 30 years, so it just set there unused for a long time, and then would not work when needed. Had a problem last summer with a window AC, they require that ground fault plug on the end, and the contacts in that prevented operation, the DeoxIT fixed that problem as well.

 

[tevans9129]

Intermittent problems are the worst.

In many cases you just end up waiting for something to completely fail in order to find out the real problem.

That is what I am afraid, it is still working so far.

If the problem reoccurs, here are some other things to check:

RM-MN (above) beat me to the thought, but I was going to suggest inspecting and cleaning contacts in the drum switch and on the contractor.

The first thing that I checked was the drum switch contacts, had good continuity by feel and with a meter. I also cleaned them with a contact burnisher tool. There are no visible contacts that I can see on the contactor.


I also second the thought about ckecking for a reason why the mechanism in the contactor might be hanging up.

I have no idea how to do that.

Is there also the possibly that the detents in the drum switch are worn so it does not stop at the intended degree of rotation where the contacts are correctly engaged?

I do not think so, they do not look warn. I purchased the lathe new in 1972 but it has only light use. From 1984 to 2000 it was never turned on and from 2000 to 2019 probably had lesss than 50 hours of run time.

Thanks again for all of the suggestions.

Best of Luck to you,

--ShopShoe

 

[tevans9129]

I've had issues with dielectric grease on switch contacts, it will dry out and prevent switch closure. I recommend a product called DeoxIT. I use that for all switch contacts, as well USB sliding contacts and such. The smallest vial will last forever.
I had to replace a two pole switch on a Delta brand wood shaper. 240volt, and it would not break through the wax left after the oils evaporated. It was seldom used. I purchased a replacement for the switch, and tore the other one apart to see why it failed. I had used it twice in the previous 30 years, so it just set there unused for a long time, and then would not work when needed. Had a problem last summer with a window AC, they require that ground fault plug on the end, and the contacts in that prevented operation, the DeoxIT fixed that problem as well.

Thanks for the comments.

I have never used any substance on contacts with metal or woodworking equipment but I do apply a burnisher on them occasionally.

 

[Chiptosser]

Deox is what I refer to in the US.

 

[TSutrina]

The contact are very high temperature metals. Look closely and you will see oxidized metal that melted. Basically no grease in the world can take that heat, Vaporize. Almost all contacts do not rub, horizontal travel, movement of the the contact is perpendicular to the faces. The arc breaks twice for every one of the 60 or 50 cycles per second due to the voltage dropping to zero. Do not need a lubricant. (Exception is the contacts required in elevators. The regulations came about when copper was used for contacts so the regulation requires horizontal travel and the original power was DC.)