Limit/starter switch question

[jordhandson]

But doesnt the label say " To start machine pull handle outwards and up"

Ah yes good point yes I got it back to front lift the lever to start then push lever down to stop. push it further down and theres the brakes

 

[fizzy]

Hi fizzy which colchester is this for I have the master I should be able to get a photo of it tomorrow if it will help

Yes would be a great help.
I just can't understand why the plunger switches off again if pushed further down.
To get it to run when the handle is in the latch position I have to push the v shaped contacts back down.
Unplugged of course

 

[carbon]

I think you need to check the colchester student manual that was linked in the other thread. On page 7 it advises on how to set up no volt release paragraph 3 in electrical wiring. The bottom two contacts will be no volt release as they stop the current flow when in the On position so if power is restored to the lathe in the event of a power cut when the lever is up the lathe wont start. I dont have mine direct wired to the mains but have it wired through a DOL starter than works as the no volt release for mine

 

[fizzy]

So annoying. So near and yet so far.
Had the lathe 18 years never been used.
Runs like a Swiss watch without the ticking!
No wonder it has had so little use!

 

[carbon]

Swap red and yellow wires and check operation, and adjust switch. When start handle is in off lower contacts should be touching bottom two posts, when the start handle is raised the spring contacts should be touching the top posts not allowing the machine to restart if power is reconnected with handle still raised.

 

[Pete.]

Swap red and yellow wires and check operation, and adjust switch. When start handle is in off lower contacts should be touching bottom two posts, when the start handle is raised the spring contacts should be touching the top posts not allowing the machine to restart if power is reconnected with handle still raised.

That would suggest that the NVR relay is not pulling in and the motor is only getting power in the switch's null zone. Might be that someone has switched the wires because they could get it to work like that perhaps?

 

[fizzy]

That would suggest that the NVR relay is not pulling in and the motor is only getting power in the switch's null zone. Might be that someone has switched the wires because they could get it to work like that perhaps?

That is quite possible.
When I bought it the old owner warned me something about the electrics - but it was 18 years ago

 

[carbon]

I don't think its a relay that's involved with this, its purely a mechanical NVR that breaks the supply to the contactor coil when the start handle is moved a certain amount. The fact that is doesn't switch at exactly the same time as the upper switch contacts allows it to work. Makes sure the supply to energise the coil is available until after the top contacts are closed so can cope with different operating speeds of the start handle. Once contactor is energised its possible to keep it energised without the spring loaded switch. May not be the best way of describing it but how it could work to me.

 

[fizzy]

There is a video of a full strip down of the switch - still none the wiser!

 

[carbon]

But did you notice red and yellow wires different way round to yours?

 

[fizzy]

But did you notice red and yellow wires different way round to yours?

I did yes - wondering if it mattered with 3 phase?

 

[carbon]

You are not switching the main power with the limit switch even though the wires are the old phase colours. The limit switch only switches on the coil that energises the contactor that then switches on the motor. If they are not connected in the correct order then it could be why you are having the problem you have

 

[carbon]

As it works if you manually push the spring loaded switch down it would indicate to me that the yellow wire is the one that energises the contactor coil and red one is the NVR connection. Swapping the two should get it working correctly but may require some adjustment of the ‘switch actuating bolt’

 

[fizzy]

As it works if you manually push the spring loaded switch down it would indicate to me that the yellow wire is the one that energises the contactor coil and red one is the NVR connection. Swapping the two should get it working correctly but may require some adjustment of the ‘switch actuating bolt’

Another night owl - I will give it a try tomorrow - is it likely to go bang if your theory is wrong?

 

[carbon]

It hasn’t already has it? You have already had both the red and yellow wires connected through the switch to the blue wire without any reported problems, but I’d advise you not to stick your finger in there with it powered

 

[fizzy]

Well I tried it.
Nothing at all sadly

 

[carbon]

Think you need to check where the other ends of those wires are connected then and see how it differs from the wiring diagram

 

[fizzy]

Think you need to check where the other ends of those wires are connected then and see how it differs from the wiring diagram

Yes I will take the front panel off again.

 

[jordhandson]

Sorry fizzy I couldnt get a photo of the inside of mine today I forgot the rear splash back covers it all and its a lot of work to move the lathe out sorry

 

[fizzy]

Sorry fizzy I couldnt get a photo of the inside of mine today I forgot the rear splash back covers it all and its a lot of work to move the lathe out sorry

It's ok thanks anyway. Not easy things to move!