Check all the interlock switches on the covers. Check there is 12v or 24v whatever it uses getting to these switches in case the power supply has failed. Also check f it works any better set to reverse.

Can you post a photo of what you originally had and what you have now. You say you have now got a contactor button AND a stop/start. I’m assuming it is new to you but not a new machine from Warco.

These lathes tend to have a NVR switch – No Volt Relese unit. Usually if you have to hold down the green start button that indicated that the coil inside has gone and is not holding the switch on. Direct replacements should be available and you should not need two separate items..

It does sound very much like a faulty NVR switch. I had to replace mine (WM280) earlier this year after 17yrs service. It started out by switching off while making a cut then eventually the green button would not hold in. Taking it apart showed overheating coil that had melted some of the surroundings and softened the springs.

If you look at the sides or back of the old one it should have a part number, put that into google and ebay and you should find a direct replacement so the wires you have will all have somewhere to go.

As far as I am aware the old ones did not light up, if your new one has an indicator light then that may need sone different wiring which could be complicating the issue.

No there is a coil within the NVR switch that when you push the green button in and allow the current to flow created a nmagnetic field which then holds the green button down when you take your finger of th ebutton. Sound slike your sis not being held down and that is why the motor stops when you take your finger off the button.

Interlocks & fuse sound OK as the motor would not even start if they where not operating correctly.

SOD.
In your simplified sketch you have two normally open contacts in parallel in the NVR. I think one (the stop) should be normally closed and in series with the coil.

Robert.

May not matter much, because the NVR has already been replaced, and a new one is unlikely to be faulty.  We hope!   So the exactly  how the relay is wired to latch power-on is irrelevant to Joner1.

As fitting a new NVR didn’t help, the issue is more likely to be in the chain of safety switches, which is much the same in this family of lathes whether fitted with DC Motors or 3-phase/VFD.

Would be useful for Robert to post the alternative NVR circuit though.

Since the lathe runs when the NVR is held down manually, we know the fuse, contactor, motor and electronic speed controller are all OK.  So the fault is most likely in the easy to fix switches and wiring, not the costly parts.

Be nice if Joner found the problem was simply the e-stop locked down, waiting to be manually released:  still catches me out occasionally and I have a bad habit of assuming any fault must be the worst possible.   Have to stop myself turning on a soldering iron and replacing all the mosfets!  Last time my lathe wouldn’t start, I did my ‘don’t assume anything’ routine and found it was switched off at the workbench.   As the workshop has a master-switch I never turn-off at the bench… Except I must have, blush.

Ta

Dave

Sorry Dave, Day job get in the way 🙂
NVR circuit

Is that an exact replacement for what was there?

Make sure you have the latching version of the switch not momentary as a quick google suggests you can get them in either option.

It also shows a NVR switch on the wiring diagram that Dave posted, assuming OP has same model.

Probably this style but depending on year and motor type they can vary, hence why I asked early on for images and if brushed or inverter. Can’t really go by a user manual as some can show 3 different switches in the same manual for the one machine!

On a break. There are two possibilites I can see that match what we have been told and can see in picture:

1/ The design requires a magnetically held “Start” switch and the replacement is not.
2/ The holding contact on the contactor is faulty

Trouble I have is I can’t see any live feed TO the Start / Stop switch Assembly on the schematic with the unit OFF. This is needed to energise the contactor.
BUT the motor runs when button pushed so there must be a feed. Either the schematic is wrong or the contactor is a bit odd. Hence my earlier comment on needing contactor details.
All this assumes that the orginal fault is a failed switch or contactor and not a loose connection.

Details / photos of orginal switch would help a lot.

Robert.