need starter gear for my 3phase mill

[Brad93]

I’m fairly sure that the control circuit on the single phase diagram is not compliant with UK wiring regs.
Happy to be corrected.
You should not be switching the neutral even if it is the manufactures diagram, it’s a grey area to me.
I’m not 100% sure if the manufacturers design would trump the regs or vice versa in this scenario as often manufacturers stipulations on things like maintenance intervals trump regs because they have shorter intervals.
But I feel the regs would trump the manufacturer in this scenario.

That’s off Schneider’s website. Wired a grinder up like that the other day and it works fine.

 

[Tray]

It will work fine but, if you break one of the switch lines it will still be at a voltage on one side of the break with possibly not a low enough impedance to Earth to trip the breaker due to the coil of the contactor being still in the circuit but still enough power to kill you.
Also an earth fault on certain parts of the control circuit would energise the contactor and start the machine.
I just said it doesn’t comply with UK wiring regs as the neutral is switched.
Schneider supply all over the world so it may be difficult for them to show a diagram that complied with everyones regulations and it might just be that it’s easier to wire it this way due to terminal locations.
This scenario could still happen if it were wired with the phase and neutral of the control circuit wired to comply with UK regs (swapped) if there was a break in the neutral.
But there is less neutral wiring to go wrong adding an extra bit of safety.

 

[Matchless]

Do you run 3P+N+E in your workshop or just 3P+E.

Shouldn’t be too hard to wire the mill up properly.

Sparky does it for me, I don't do 3 phase.... I think it is 3p+n+e, he made me run 5 core down to the shed from memory,

 

[Tray]

Worst case scenario:
Switch line of control circuit becomes broken.
You come into contact with the switch line whilst leaning over [insert your most dangerous machine here].
You are now providing a return path for the control circuit to energise the contactor and you are being electrocuted.
The machine has started because you have completed the control circuit path and you are also being mangled/chopped/sliced or any variety of unpleasant things.

 

[fnlvder]

Wiring regulations only apply to the fixed wiring, i.e from the consumer unit to the 3 phase socket. It's not a problem to switch the neutral in the contactor in a machine that plugs in to the socket

 

[Tray]

The regulations do not define fixed wiring as far as I am aware but they do define fixed equipment.
This covers non portable machines even if they are connected to the supply via a plug and socket.
The regulations covering socket outlets up to 32A would require an RCD to be fitted which would limit the chances of the scenario I gave from happening but not eliminate it.
Haven’t got time to delve into it too far but read these.
The info is in there somewhere.
https://electrical.theiet.org/bs-7671/18th-edition-resources/18th-edition-changes/

https://electrical.theiet.org/wirin...12018-chapters-41-46-53-and-regulation-54222/

The fact that it’s safer to wire it the way I suggest should be enough reason anyway.

 

[daleyd]

I’ve seen them wired both ways, to be honest in the scenario described if it was live you were touching then it could be as bad if not worse.

 

[Tray]

Much less likely though as the resistance of the equipment wouldn’t be in circuit allowing a better path to earth which would be more likely to trip the RCD/MCB and save your skin + the machine wouldn’t have started up even if the beaker didn’t trip.

 

[Matchless]

Sparky mate turned up Friday and more or less finished my garden shed wiring! and the mill is converted back to 3 phase operation! just the Student to drag down the garden and convert back to 3 phase! need to finish rebuilding the water cooling system for the TIG and plug it in, sockets for the treadle spotwelder, TIG and mill installed, Student will share the mill socket, the Harrison has it's own socket not pictured,

 

[Matchless]

What oil? I found this flip top oil port on the gearbox of my Hayes Diemaster mill when wiring it up, I am thinking of chucking some gear oil in there, any thoughts, It seems to have been open for a while as it has some alloy chips in it, I will remove as much as I can, runs fine,

 

[Brad93]

Usually TELLUS on these older machines