Milling macine problem

[johnstantine]

I'm sure the A2 contacts are on the bottom right of the contractors looking at you photo's, just under and behind the no contact. And I would bet the A1 contact is on the top left, at the back behind L 1 contacts.

 

[mrmatt]

Sounds very much like a break in the stop circuit to me.
You can check the overload is ok by checking for a circuit across 95 and 96 with power off. You should find the circuit opens whilst you have the reset button pushed in then makes again as you take your finger off.
How did you test stop buttons exactly?

ill check the overload tomorrow

I cheched continuity across the emg stop button when the stop button is pressed the circuit is open

The user seemed to think you can operate the mill without the slurry pump on

 

[johnstantine]

ill check the overload tomorrow

I cheched continuity across the emg stop button when the stop button is pressed the circuit is open

The user seemed to think you can operate the mill without the slurry pump on

Ok. Did you check that when the stop button is reset that the circuit is closed?

 

[mrmatt]

Ok. Did you check that when the stop button is reset that the circuit is closed?

Yes it is closed once the button is reset. I initially thought it was this as the button was sticking - it isnt sticking now tho

Thanks for your imput thus far I really appreciate the help guys

 

[johnstantine]

Ok. Looking at your third photo I'm willing to hazard a guess that 0 and 2 on that terminal rail is your 24 v control. If so there's a good chance that you will have either 0 or 2 wires at the A1 terminals on the contactors behind the L 1 terminals. If there are wires numbered 0 at these A1 terminals then check for continuity between there and the 0 terminal at the terminal rail. If the wires are numbered 1 then check for continuity to the 1 terminal on the rail. This should more or less confirm that you have a common to the contactors and suggest that there is a break in the stop circuit.

 

[mrmatt]

Ok. Looking at your third photo I'm willing to hazard a guess that 0 and 2 on that terminal rail is your 24 v control. If so there's a good chance that you will have either 0 or 2 wires at the A1 terminals on the contactors behind the L 1 terminals. If there are wires numbered 0 at these A1 terminals then check for continuity between there and the 0 terminal at the terminal rail. If the wires are numbered 1 then check for continuity to the 1 terminal on the rail. This should more or less confirm that you have a common to the contactors and suggest that there is a break in the stop circuit.

From memory they are labled 0. I will check for continiuity tomorrow. If no continuity is shown does this indicate a stop issue? I took one contactor out and didnt see A1 or A2 labled but i am guessing the ones behind the 3 pases are these connections to the coil as there is nothing else in the contactor and if i remember right the ones labled 0 are looped into the other contactors also

 

[johnstantine]

Also, I know you said you checked the stop buttons but, you could completely eliminate them by shorting out the two wires on the buttons then trying to run the machine. Just be ready to hit the isolator if it all goes wrong.

 

[Hawk81]

have you tried the reset button on the overload

 

[johnstantine]

From memory they are labled 0. I will check for continiuity tomorrow. If no continuity is shown does this indicate a stop issue? I took one contactor out and didnt see A1 or A2 labled but i am guessing the ones behind the 3 pases are these connections to the coil as there is nothing else in the contactor and if i remember right the ones labled 0 are looped into the other contactors also

You should (in theory!) have continuity from terminal behind L1, all the way to the same numbered terminal on the rail and also right through to one leg of the secondary on the control transformer. If you DO have good continuity from transformer right through to contactor then it suggests problems is on stop circuit.
Think of the terminal behind L1 as being a bit like a neutral, in that you wouldn't expect that leg to be switched.

 

[johnstantine]

If the wires going to the terminals behind L1 are numbered 0 then you should have 24v between them and the terminal 2 on the rail. If this checks out then you need to trace from terminal 2 right through to start buttons and stop buttons. There should be 24v between terminal 0 and one side of start buttons, if so there should be voltage between terminal 0 and each side of stop buttons.
Do the pump, traverse, and motor each have their own start and stop buttons? or is there one stop button that stops everything?

 

[silva.foxx]

So... by now, mrmatt, you would have drawn up a schematic of what you have. You are the best man for that job. 3 DOL starters and stop/start circuits. You should then be able to trace the circuit for continuity from +24v through components through to coils. Put temporary shorting links in to test (hence the importance of drawing up the schematic).

You will get there. You will do it. You'll find the fault and think "Is that all it was?" and may feel a little embarrassed that it was something so simple or so obvious. I've had plenty of them and certainly not alone! Good luck.

 

[silva.foxx]

What details have you got on the milling machine?

Make

Model

Perhaps a schematic can be sourced on t'interweb.

 

[caddy]

There is 24v out of the transformer for the control gear traced this to the start buttons. There are 3 start buttons, one for each contactor, and 4 stop buttons one for each contactor and and Emg stop. The emg stop functions correctly I have double checked this.

Do you get 24v back to tha panel connections when you press the start button ? if so then where does the cable go from there.

 

[ACDC]

Out of curiosity, have you checked the resistance of the contactor coils? if they have gone t**s up, you will lose your retaining circuit if it goes through a N/O contact on the contactor.. Just a thought before you start ripping out cabling.

 

[silva.foxx]

Is our miller running yet?

I'd have sacked you by now!