2 speed switch wiring - 3 phase motor

Hi there

I am hoping someone may be able to chime in with some advice on wiring up a switch that is on an old BCA Jig borer. The machine has a 3 phase 2 speed motor. The three phase power comes into the machine stand isolation switch and then from there to the two speed switch. On the power input side to the switch there are 4 wires - the three phases and an earth. On the motor side there are 6 wires and happily they are tagged with wire identifier and these match up with the switch terminals so this all seems very straight forward and matches the wiring diagram I have which I have attached a pic of.

https://uploads.tapatalk-cdn.com/202...8978acf998.jpg


Here is the switch

https://uploads.tapatalk-cdn.com/202...e6501bc42b.jpg

https://uploads.tapatalk-cdn.com/202...2125d50363.jpg

My confusion is that there is no obvious terminal to run an earth wire (the 4th wire come in on the power side of the switch). I am not sure where this should go?

Interestingly there is one terminal that has been left wired as shown below - this is the only wire that was left on the switch and all other wires were tagged and it is obvious where they go. B1 green wire connect and then there is the black wire to the only terminal on the switch that doesn’t have a label on it which has made me suspicious of it and if.
https://uploads.tapatalk-cdn.com/202...8155270822.jpg

So can anyone shed any light on where I should be looking to send the earth to?

Hi Danger Mouse,

The earth wire goes to the frame or body of the machine ! In the case of the switch it would probably be under one of the screws that fasten the switch to the machine.

Quote:

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Originally Posted by BaronJ

Hi Danger Mouse,

The earth wire goes to the frame or body of the machine ! In the case of the switch it would probably be under one of the screws that fasten the switch to the machine.

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Thank you Baron, that had been my first thought and then I started to second guess myself.

Hi,

Is there any single phase required on the machine?
One thing to watch for on old machines is earth used as neutral.
I don't think its the case here but I wonder where the other end of that green wire is.

Quote:

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Originally Posted by Stustoys

Hi,

Is there any single phase required on the machine?
One thing to watch for on old machines is earth used as neutral.
I don't think its the case here but I wonder where the other end of that green wire is.

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From the switch there isn’t any single phase and I have it running successfully now. Interestingly on the machine from the initial isolation switch a single phase line does go to another box that seems to have a transformer and outputs a DC current that connects to a lamp. The reason I say it appears to do this is that the end of the light has a 2 pin polarised plug like you see in caravans and other 12v outlets. The wiring here is all connected and no need for me to touch it.