Centroid Community CNC Support Forum

Okay I think I've got the Transformer, cap, contactor, power supply, and limit switches figured out and wired in. Now we're back to the spindle controls. I'm assuming the board on the bottom left is going away. The line input is coming in in the top right corner. Next it goes through a rotary disconnect switch then through the large fuses and up to the relays in the top left and middle. I'm thinking the relays in the very top left are for forward and reverse? Does this all sound correct so far? I'm thinking that the centroid control could run those forward and reverse relays correct?

Next question, thinking about the encoders, i think this is a tach in the ends of my servos, i don't think i will need those right? I'd like to remove them to make room for encoder wiring.

Do you have the original schematics for this system? Otherwise, you'd have to trace wires to determine where the contactors (3 big relays up top) go. It looks like the spindle speed control was mechanical so it makes sense for there to be some contactors for forward/reverse running. I'd also expect at least one for the axis servos.


You probably would not need that board with relays unless the relays on ALLIN1DC cannot handle the loads. In that case, using the ALLIN1DC relays to control beefier external relays is the way to go.

Yep, those are the brushes and commutator for the tachometer. ALLIN1DC does not use tachometers and so that is probably where the encoders should be mounted.

Yes, the things in the top left are a reversing contactor assembly, with an overload relay (collectively called a "reversing starter").

Yes, you can control them from the Centroid control for spindle forward/reverse/off. You will not, of course, have programmable speed control.

Here's a diagram I made of the forward and reverse relays. Looks like it's controlled by 110 volt AC circuit with some safety auxiliary contacts to prevent both relays from being on at the same time. What's the best way to control this with the all-in-one?

Here's what I'm thinking if I can find two 24 volt DC controlled relay to apply the 110 volts to the main spindle relays. Does this look reasonable?

I would just wire the 120VAC for the contactor coils through the OUT7 and OUT8 relays on the Allin1DC. I believe they are rated for up to 250VAC, and the current draw of the contactor coils is minimal.

It is generally not necessary to use a relay to control a relay to control a relay.

So just go something like this? I'd assume I'd want to use the 110 volt off the tb1 and the common off the tb1 correct,

Don't forget snubbers across the relay coils!

tblough wrote: ↑Thu Jan 30, 2025 9:26 pm Don't forget snubbers across the relay coils!

That's not something I'm familiar with, what is it? ( I'm guessing something to do with voltage Spike when the coil unloads) where do I get it? and where should I put it?