Wiring a plug for my Harrison Milling Machine

[angusb]

Hi All,

Having got a static 3 phase converter with idler motor to power my Harrison mill, the next step is to put a plug back on the mill so I can connect it to the output on the phase converter. When I got it, the mains plug had been cut off leaving 6 wires which had previously been connected to the mains. I have traced these and confirmed with continuity on the meter what 4 of them do:

L1 = Brown wire connected to the main rotary isolator on the side of the mill labelled L1
L2 = Black wire connected to the main rotary isolator on the side of the mill labelled L2
L3 = Grey wire connected to the main rotary isolator on the side of the mill labelled L3
Earth = Yellow and Green wire

Below is the back of the main rotary isolator on the side of the mill

Then there are two other wires, both brown. One goes to a blue wire on the red and yellow emergency stop pedal you can press with your foot under the front panel. The other goes to the red stop button on the front panel.

The back of the front panel looks like this:

The mystery brown wire going to the stop button on the front panel is the one going into the orange side of the orange and green switch in this picture above, the output from this orange switch goes to a terminal behind the one labelled 13 on the contactor labelled 21.
The other mystery brown wire goes to the emergency stop pedal. Out of that pedal there is a brown wire which is joined to a red wire in a bundle of cables that terminate on the main rotary isolator on the side of the mill. This wire is one of the two in the photo of the back of that isolator, and they are labelled C1 and C2 on the isolator. I've tried testing them for continuity with the meter but get nothing, I thought maybe because it is going through the stop pedal that has broken the continuity?

I know I need to wire up a 3 phase and earth plug to the L1, L2, L3 and Earth wires but I don't know what to wire the other two brown wires to for the stop button and stop pedal.

Can anyone point me to somewhere which explains how these switches should work or possibly explain it to me if you understand it please?

Thanks for any help you can give me.

Angus

 

[carbon]

Is the connector circled in yellow connected to the stop switch?

Looking on the RDM engineering website the stop pedal seems to be associated with there drivloc product to brake the motor with an electronic dc injection brake. Is there any evidence of this system on the mill?

All conventional stop switches must be wired in series so pressing any one stops the machine.

 

[Brad93]

Driveloc is a flipping nightmare - if it's faulty it will cost you a small fortune to put right.

 

[Brad93]

You should not have more than 4 wires coming down to your plug

 

[angusb]

View attachment 517035

Is the connector circled in yellow connected to the stop switch?

Looking on the RDM engineering website the stop pedal seems to be associated with there drivloc product to brake the motor with an electronic dc injection brake. Is there any evidence of this system on the mill?

All conventional stop switches must be wired in series so pressing any one stops the machine.

Yes, the brown wire from that connector you have circled goes to the emergency stop pedal. The inside of the pedal has this switch in it

and the other cable coming out of that pedal goes to one of the mystery brown wires. I don't think there's a DC brake in the mill, could there have been one attached to the switch external to the mill?

 

[Brad93]

That's fine it's just a NC switch.

I would suggest starting fresh.

L1, L2, L3 & PE coming down a piece of H07 cable preferably.

The foot pedal needs to go in series with the emergency stop switch.

 

[angusb]

You should not have more than 4 wires coming down to your plug

Thank you. The 6 wires are all in the flexible conduit from the main isolator. I guess they didn't all have to have been wired to the same plug?

 

[Brad93]

I don't know why they've taken that up to the isolator.

 

[Brad93]

Have you got a picture of the isolator

 

[angusb]

Have you got a picture of the isolator

This is the isolator from the outside

and this is the inside

 

[angusb]

The wires from the plug to the isolator go into the flexible conduit that also has these 2 brown wires in it. You can see the circular cover to the conduit next to the isolator in the middle pic above of the inside of the isolator.

 

[Brad93]

What I don't like is the isolator should do exactly that, isolate the machine. There should be no other power circumventing the isolator and going down to the panel.

 

[knighty]

I'd be willing to bet there was a small box with a contactor in it on the end of that wire and then the plug wired into that

would explain why the emergency stops where wired there

or... maybe an inverter?

 

[addjunkie]

You should not have more than 4 wires coming down to your plug

Five wires are common in a 3 phase 5 pin plug…6 is a new one on me.

Get a wiring diagram, then trace the circuits and update it to what you have. Foot switches have often been added later in life.

 

[angusb]

There is no wiring diagram for these Harrison mills as far as I can tell. I've searched and have read that all the documentation was destroyed when the company stopped making them. There are manuals but no wiring diagrams. I've found a few articles where people have converted them to VFDs but none where the original wiring is detailed.

I think my next step is to trace all the wires out and then work out where to wire in the stop switch and stop pedal in series to actuate the contactor to break the connections to L1, L2 and L3. Looks like there was something else wired to the stop switch and pedal before it was removed from its last home but I just want to make it work the way it was originally designed, albeit with the aftermarket stop pedal in series with the stop switch.

Thank you all for your help so far.

Angus

 

[m_c]

I'd be willing to bet there was a small box with a contactor in it on the end of that wire and then the plug wired into that

would explain why the emergency stops where wired there

or... maybe an inverter?

This would be my guess too.
Most likely been in something education related, and you'd probably find that there was also an external emergency stop system, so machines could all be stopped remotely.

 

[Brad93]

There is no wiring diagram for these Harrison mills as far as I can tell. I've searched and have read that all the documentation was destroyed when the company stopped making them. There are manuals but no wiring diagrams. I've found a few articles where people have converted them to VFDs but none where the original wiring is detailed.

I think my next step is to trace all the wires out and then work out where to wire in the stop switch and stop pedal in series to actuate the contactor to break the connections to L1, L2 and L3. Looks like there was something else wired to the stop switch and pedal before it was removed from its last home but I just want to make it work the way it was originally designed, albeit with the aftermarket stop pedal in series with the stop switch.

Thank you all for your help so far.

Angus

No need to do that - it's a really simple system.

You've got two contactors, a start button NO, a stop button NC, a spindle direction switch and presumably a coolant pump switch.

The first contactor (with the large numbers 21) is for the spindle by the looks.

The second contactor with output cables A,B,C seems to disappear off into the machine. I'm guessing a table motor for x-axis travel? Must have a separate button or switch somewhere?

Tell me what the second contactor is for and what sort of button/switch controls it and I can draw you a diagram.

 

[Brad93]

Five wires are common in a 3 phase 5 pin plug…6 is a new one on me.

Get a wiring diagram, then trace the circuits and update it to what you have. Foot switches have often been added later in life.

No neutral on this

 

[addjunkie]

I'd be willing to bet there was a small box with a contactor in it on the end of that wire and then the plug wired into that

would explain why the emergency stops where wired there

or... maybe an inverter?

Perhaps join the two spare wires. And test the stop buttons.

No neutral on this

I know.

 

[carbon]

What model is it as there are some wiring diagrams on this very website Wiring diagrams