problem with a warco 250 v lathe electrics

[joner 1Participant @joner-1]

[Robert Atkinson 2Participant @robertatkinson2]

Can you take a picture of the markings on the old and new switches?
One way to make them smaller if you use a PC is to open them on the PC, use the snipping tool in Windows to select the useful area of the image. Then click the save icon and save it as a jpeg to your PC. Then upload that image to the forum.

There do not seem to be enough connections to the Start/Stop switch for the new switch is the wrong type. You can put the wiring back as it was.
Information on the contactor (in the back of the lathe) like make and part number would be very useful. There is no information on the parts in the manual.
While you are looking at the contactor check all the wires are secure and terminals tight. A loose connection on the contactor could cause the fault described.

Robert.

[JasonBModerator @jasonb]

Robert this may help. it is for a VFD equiped version of the lathe not what Dave posted but may not be exactly what the OP has.

His image shows 3 wires to/from the new switch plus a loop (hard to see one brown wire under the switch), that also seems to match what is on the schematic.

[joner 1Participant @joner-1]

Hi no this is what they replaced the older switch with werco don’t have any other switches for this machine.

[Robert Atkinson 2Participant @robertatkinson2]

Hi Dave,
I sound that schematic as well. I was having trouble sorting out the contactor terminal designations. I’v now sorted it.
Note that the live and neutral identifications are swapped on that schematic.

IT appears the the Normally Open (NO) contacts on the contactor, or their connections are at fault.

From the older circuit:
Permanent live on the contactor Coil (A1)
Circuit from other side of coil (A2) to the (NO) Start switch (Right Hand 2).

When Start pressed circuit from Start (Right Hand 1) to E-stop , through guard switches and ON /OFF/Reverse switch (10,9) to Neutral.

We know all the above works because the lathe runs if Start switch is held. This is where it goes wrong . The Stop Switch which is normally closed (NC)  des not make sense with a link from the Left hand 1 & 2 terminals. This circuit goes nowhere.

However if we link RH 1 to LH 2 (i.e. short brown wire across not up and down) it will work.

So when the contactor energises on pushing Start the NO contactor contacts (13NO & 14NO) close. This connects A2 throug the NC STOP switch through the repositioned link through the E-stop & guard circuit to neutral. When you press Stop this opens andcontactor drops out.

So the fix is move the short brown wire from the terminal with the other brown wire to terminal on the other side of the switch (at the Bottom in the picture) This may mean moring the brown wire from the contactor to the TOP terminal (currently with single brown wire) so the linking shorting brown wire can reach across the bottom of the switch. This connects a brown and blue wire to the same terminal which sounds wrong…
All the above assumes the start / Stop switch terminas are Start on one side and Stop on the other which is what is shown in the photo.

View on back of switch

Robert.

[Robert Atkinson 2Participant @robertatkinson2]

Hmm,
The missing posts issue I still on the Forum.The picture of the contactor and VFD was not vissible to me when I wrote the post above

It may be file size related. I noticed that Joiner1 has the image on his profile at 4Mb here is a compressed version of that one with more visible terminal markings than the one above.

So This brings up a couple of additional points

First it confirms they have a VFD equipped model so diagram posted by JasonB (which I wrongly attributed to Dave SOD sorry to both for that) is the closest we have.

Second the lathe is not wired exactly to that as there are two brown wires on terminal 43NO. This could still conform to the INTENT of the diagram if one of those wires goes to A1 etc.
It does make fault finding very difficult without being hands on with the lathe.
That said my comment on the previous post that the link wire on the switch is wrong (you can see through the contacts clear plastic and the wire is across them) and my sketch is correct so start there.

As an aside it is very bad practice to use brown and light blue (mains colours) for control wiring. Doing so would cause a machine to fail a informed CE/UKCA conformity assesment. The makers are being cheap by not using a third colour.

Robert.

 

[SillyOldDufferModerator @sillyoldduffer]

Hmmm, can’t help much at the moment – still unwell enough to spoil my concentration.   However:

Joner said: “Later on werco called me back and suggested to wire the switch the other way round ? so I did the lathe runs after I twisted the stop button out and I never pressed any buttons . but I had to hold the red button in to stop the lathe .”

Wrong, but not far off!   That this is the VFD version of the lathe makes no odds I think because the lathe runs when the switch is held down.   The fault is either the NVR switch, possibly due to being wired differently from the original, or – maybe – in the chain of safety switches as discussed earlier.

First thing is the wiring of the new switch; it has to be right.  Does the switch have a part number or – even better – a circuit diagram?  The diagram might be on box, or embossed on the body of the switch, or – more likely – on a slip of paper inside the box.  It’s unfortunate that these lathes aren’t identical – several variations, all minor, but confusing.  Diagnosing at a distance is tricky, reminds me of the first time learner pilot who was talked down by the control tower after the instructor had a heart attack!

Where are you Joner?  Might be help nearby. Robert armed with a multimeter would nail this in less than 10 minutes…

Dave

 

[Robert Atkinson 2Participant @robertatkinson2]

Hi Dave,
Sorry you are unwell.
I’m pretty sure the the correct switch assembly is not a NVR / magnetically held type and the replacemen is suitable.
I don’t know what the original fault was (maybe is it might still be there) but there is definitely a problem eith the wing of the new switch. The brown link wire is connected across the NC stop switch contact. This is patently wrong as it stops the circuit being opened.  The link should be providing a common connection between the start and stop contacts.
The NVR function is provided by the contactor via the 43/44NO contacts.
I did send Joiner a personal message.

Robert.

[Robert Atkinson 2Participant @robertatkinson2]

I got a personal message from Joiner1 a couple of days ago. Changing the brown link wire as I suggested fixed the problem 🙂

I suggested he added to the thread to close it off but as there has been nothing I thought I’d do an update.

Robert.

[joner 1Participant @joner-1]

Hi all thanks for all the people that tried to help me, but a big thanks to Robert Atkins 2 he nailed it thank you Robert it works 👍

[SillyOldDufferModerator @sillyoldduffer]

Hurrah, well done Robert and Joner for fixing this and reporting back.

Very useful to know that this variant doesn’t use an electromagnetic NVR switch.    Top marks to Robert who suggested early in the thread that NVR was provided by the contactor and followed that up.

There’s a problem with most machine circuit diagrams in that they usually only show major components as black boxes.  Hard to diagnose when there’s no clue as to what’s inside the box.   Debugging is made even harder by working remotely.  When the diagnostician has access to the machine, quite small visual clues give the game away!  And if necessary stuff can be dismantled to reveal all.  Only do post mortems if you know what to look for – the patient may not be dead!

Dave

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