Help with Spindle wiring identification

[Shinosky]

Hey everyone. I am new here. I just purchased an Acorn in preparation of upgrading my ShopSabre 23 with new motors and controller. I have some experience doing this kind of thing but I am not "really" an electronics guy. I have been going over the schematics and planning out the new control box. I have a pretty good grasp on how to proceed until I took a look at my spindle. I was expecting a single power cable running to it from the VFD. There are an additional 2 wires. One I'm assuming is the 24V power for the electric fan. The other I am not certain about. I suspect a sensor but I am not sure. The control box is a bit cramped and jumbled so I can't trace the wires easily. That and the fact that there is no breakout board in the control box. It all runs back to a daughterboard in the PC.I was hoping somebody here may be able to identify it for me. Trying to identify this from the literaure I possess has been futile. I need to know it's function and how it ties back into the board. The existing control software is WinCNC. It is a solid controller but they make it very difficult to upgrade anything or do anything out of the ordinary. That's one of the reasons I am switching over to the Acorn. I know this is probably a small thing for some but I am learning as I go. Thanks for any help.....Andy

[Gary Campbell]

The one marked "sensor?" Is for sure a 24v fan connection. The other may be, and I repeat, may be, the internal thermistor. Only knowing the other ends connection, or having a wiring diagram would tell you for sure

[cncsnw]

I think Gary nailed it.

[Shinosky]

Thanks Gary. I have been watching a ton of your videos lately. You are the man. After I posted this I realized I may have had those reversed. Best I can probably do is figure out which pin on the connector it is connected to. Trying to figure out how to do things in WinCNC is not very intuitive. I feel like all the info I need is buried somewhere....

[Shinosky]

Good Grief! You figured that out from that drawing? I had come across that drawing when I was trying to figure this out. The only thing I could take away from it was that the fan was 24V. That's all I could understand.....I am only slightly smarter now than when I started.

[ShawnM]

I agree with Gary after seeing the schematic posted by cncsnw. The leads are labeled "bi-metallic" which are wires going to the bimetallic strips in the air cooled spindle to measure temperature. Since it's air cooled this sensor probably controls the 24v to the fan to possibly turn it off and on and/or throw a fault if it overheats.

[Shinosky]

Thanks Shawn! I think that will give me more to go on when I begin to dismantle the existing control box. I hopefully will be able to figure out the logic at that point.