[moriseikimark]

Hi guys,
Im retrofitting a Bridgeport boss 6 milling machine.
I have replaced the steppers with servos.
I have removed all unnecessary electrical equipment.
Im running mach 3.
What im having a problem with is wiring the spindle starters.
I would like to keep the original fwd/rev switch but Im not sure how to wire it.
The machine still has the original wire # tags making wire identification easy.
Im hoping someone out here has done exactly what im trying to do and can help me out.
Thank You in advance

[cncsnw]

I assume you want to have both automatic (programmable) control and manual control.

You need to sit down and define how you want it to work.

Will there be a manual/auto mode switch, so that only one kind of control can work at a time?

If not, then what should happen when a manual request (turning the switch on the head) comes in while running in auto mode? What if the direction conflicts?

What should happen if an auto request (programmed M3 or M4) comes in when running in manual mode? What if the direction conflicts?

Once you define how you want it to work, then it is fairly easy to design the wiring and/or PLC ladder (depending on how you choose to implement it).

Your reversing starter should have normally-closed auxiliary contacts on each side. When you wire power to each coil (forward side and reverse side) you need to route that power through the opposite auxiliary contact. This ensures that you can never try to pull in both sides at once, causing a line-to-line short.

I would use the manual barrel switch on the head to send logical inputs to the PLC (which could then decide whether to pull in either side of the starter). Alternately you could use the manual barrel switch to power to starter coils, in parallel with your PLC outputs, but perhaps enabled only when a manual/auto mode toggle switch is in the manual position. You almost certainly do not want to continue running the 3-phase power through the barrel switch, as that would not play well with automatic-mode control.

What kind of PLC I/O system do you have available?

What do you envision for manual-mode / auto-mode selection?

Finally, but foremost, you need to ensure you have a bombproof way to ensure spindle power gets turned off when you press your emergency stop button. Don't trust your PC software or PLC logic to do this; make sure it happens with direct switch contacts and relays (e.g. E-stop interrupts all coil power to the spindle starter, or interrupts coil power to an upstream contactor that cuts off the three-phase before it gets to the spindle starter).