Discuss Multiple machine 3 phase emergency stop system in the Commercial Electrical Advice area at ElectriciansForums.net

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ACL

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I have been asked by a friend if I can supply an emergency stop system to their wood working machine shop where 3 E-stops will kill all 11 machines at the same time.
My question is, is there a system out there already that I can purchase or do I have to just get a large enclosure and many contactors to do this?

Many thanks in advance for any help.


ACL:coffee:
 
Usually you build it yourself, the unlimited varients make maketing a one brand covers all impossible, just build a control panel with say 24dc control circuit pulling in a large contactor and if possible have it killing the supply to a dist' board that the machines are fed from..alternatively several contacts looped together for the individual machines.. just few of many options, ensure all machines have control circuits that will drop out on power failure and wont auto-start when power is re-instated, and you incorp' a reset button or key op' so resetting the acted E-stop dosn't bring back supply either.
 
Unfortunately I can't kill the Dist board as the lighting circuits are also supplied from the same board so it looks like a large enclosure with multiple contactors for me.


Thanks for your help.

regards

ACL
 
Doing an emergency stop circuit for this is not just about cutting off the power.What you have to do is do a risk assessment of what injuries can occure, and from that what catagory of stop you are going to need.
You may need the wood working machings to stop dead if there is an accident and cutting off the power would just let the machines free wheel to a stop.
Also if there is an accident the injured person may try and sue you, as you designed the system.
 
You are correct spoon but thought that goes without saying but if the OP finds he dosn't want the design responsibility bearing down on his shoulders then it may be possible to extend the E-stop circuits of each machine through a safety relay which in turn is controlled by the new E-stop system that way you keep the original design as is leaving machine with power and only open circuiting each machines E-stop.... the issue of whether the machine complies to modern reg's would need to be thought about though, this is probably the cheaper option too as opposed to multiple contactors dropping power.
 
I agree with Spoon - let me add that if you connect to existing Estops on machines you should use a safety module for emergency stop - they are made by companies like Telemecanique, Pilz, Siemens and provide extra safety features at low costs (checking Estop pushbutton functionality, safe contacts redundancy and monitoring etc) - for instance see XPS modules from Telemecanique
 
You need to look in to this very carefully. As has been said just cutting the power isn’t an option with some machines. You will need drawings of each machine, of you will have to make your own.
Bear in mind it’s your neck on the line if you get it wrong. Looking at your previous posts I would guess industrial isn’t your field.
 
I am at present talking to the machine supplier about each individual machine and how each one operates in relation to their existing emergency stops on the machines.
They have indicated that they can carry out an E-stop systems for more complicated installations.

I take on board all the information about making sure the machine will stop correctly and that it's my neck on the line if it goes wrong.

It's good to keep on learning!
 
As has already been mentioned there are some very good products for controlling E-stop, if it was me doing this i would look at each machine and tie into any existing E-stop to that machine. The ones that dont have an e-stop but say a "off" button on a DOL starter again i would tie into that starter to drop it out as if the operator had hit the button.
That way you are not making the installation any less safe than it was. Hopefully much much better.
BTW just out of curiousity why 11 separate machines all stopping at once ?

Oh just a thought, as you will be making a small panel, might be worth having a couple of indicator lights for "Control On (Green)" and "E-Stop Operated (Red)" as it might make it easier to figure out what has happened if someone leans on it by mistake...Lol
 
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As said you do need to be very careful here.

Puwer 98 now calls for nearly all woodworking machinery to have additional braking fitted where none is present.

Most machines are now required to completely stop within 10 seconds.


The list of machines is as follows......

1. circular saw benches
2. dimension saws
3. powered and hand-fed cross-cut saws (unless there is no risk of contact with the blade during rundown)
4. single-end and double-end tenoning machines and combined machines incorporating a circular saw and/or tenoning attachment
5. narrow band saws
6. re-saws
7. vertical spindle moulding machines (unless fitted with a manual or foot-.operated brake)
8. hand-fed routing machines
9. thicknessing machines
10. planing /thicknessing machines
11. surface planing machines.
 
You can't remove power from any emergency system on wood machines if this causes the cutters to stop in excess of that required by PUWER98.
You can't remove power from any emergency system instantly that is designed to "run-on" after machine stops to provide safety related "things" such as LEV.
If you are going to link machines and undertake a design like this you will need to have access to all of the relevant standards and statute law documents and a full understanding of them, as IF anything goes wrong, you will be the one liable.
If the machines are CE marked then you could have modified the machines which would negate the CE marking, and thus you would then be legally responsible for all of the safety aspects of that machinery.
IF you don't have a full understanding, then you really should get someone in who does.
YOU need to ask WHY this is being requested.
This is similar to school central switching systems under 4163, I have never seen one yet implemented correctly according to statute law, BS's etc.

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Oh, the relevant standards will be over £1k alone.
 
BTW just out of curiousity why 11 separate machines all stopping at once ?

Their theory is that if one operator is at the other end of the workshop and gets caught in the machine then they can stop the machine from the other end of the workshop.
I think they had this system in their training center and thought that it would be a good idea for their workshop.
 
You can't remove power from any emergency system on wood machines if this causes the cutters to stop in excess of that required by PUWER98.
You can't remove power from any emergency system instantly that is designed to "run-on" after machine stops to provide safety related "things" such as LEV.
If you are going to link machines and undertake a design like this you will need to have access to all of the relevant standards and statute law documents and a full understanding of them, as IF anything goes wrong, you will be the one liable.
If the machines are CE marked then you could have modified the machines which would negate the CE marking, and thus you would then be legally responsible for all of the safety aspects of that machinery.
IF you don't have a full understanding, then you really should get someone in who does.
YOU need to ask WHY this is being requested.
This is similar to school central switching systems under 4163, I have never seen one yet implemented correctly according to statute law, BS's etc.

- - - Updated - - -

Oh, the relevant standards will be over £1k alone.


Sounds like it could be a nightmare to get involved in. I am in the process of getting the information for each machine, but it still sounds fraught with problems.

Thanks for your input.

- - - Updated - - -

As said you do need to be very careful here.

Puwer 98 now calls for nearly all woodworking machinery to have additional braking fitted where none is present.

Most machines are now required to completely stop within 10 seconds.


The list of machines is as follows......

1. circular saw benches
2. dimension saws
3. powered and hand-fed cross-cut saws (unless there is no risk of contact with the blade during rundown)
4. single-end and double-end tenoning machines and combined machines incorporating a circular saw and/or tenoning attachment
5. narrow band saws
6. re-saws
7. vertical spindle moulding machines (unless fitted with a manual or foot-.operated brake)
8. hand-fed routing machines
9. thicknessing machines
10. planing /thicknessing machines
11. surface planing machines.


They have all these machines, thanks for the PDF.
 
I am guessing that the PDF that Lenny has posted is WIS38, which is just the tip of the iceberg.

There are also many other statute law documents, ACoP, CoP & "Formal" guidance that is relevant.

This is not something you should take on lightly, it is bread and butter for some, but not others.

I strongly recommend that you have PII to cover this work, and that you ensure that you have tail off cover if you take on the work, as you would be taking on a LOT of responsibility which would not end once the job is done and could go on for perhaps 10 years after.
 
Their theory is that if one operator is at the other end of the workshop and gets caught in the machine then they can stop the machine from the other end of the workshop.
I think they had this system in their training center and thought that it would be a good idea for their workshop.

OK, makes sense, they should all be braked by now and have hopefully provisions for remote stops.
 
I am guessing that the PDF that Lenny has posted is WIS38, which is just the tip of the iceberg.

There are also many other statute law documents, ACoP, CoP & "Formal" guidance that is relevant.

This is not something you should take on lightly, it is bread and butter for some, but not others.

I strongly recommend that you have PII to cover this work, and that you ensure that you have tail off cover if you take on the work, as you would be taking on a LOT of responsibility which would not end once the job is done and could go on for perhaps 10 years after.


I'm getting a strong sense that this is riddled with pit falls. I liked the idea of being involved at the start but now thinking it would be better left alone.
 

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