This is a new one for me… today, out of the blue, while in between prints, the exhaust fan on one of our units suddenly started revving, up to what I have to assume is way beyond it’s intended top speed. We have external exhaust/filtration systems built in, so we have the fan toggled off… this is some sort of software/hardware glitch happening. Nothing I do will cause it to turn off, but it is randomly stopping itself for a few seconds here and there, before starting up again. I did a factory reset, and the fan stopped while I was going through the wifi setup process, but started up again as soon as everything was logged back in. The machine seems to function otherwise, but the fan is running at such a high speed that it’s vibrating the whole machine and it doesn’t seem like it would be a good idea to let it keep on running this way. Any ideas what we might be dealing with here?
Wow that’s new to me. Let us know what you find out.
I would disconnect the external fan if you have an inline fan. Remove the left side cover and pull the wire.
I was able to remove the fan from a basic without removing the glass, but i removed the glass with the pro to take out the fan.
Assuming it’s a performance series, I thought the exhaust fan only had one speed. A software fault might turn it on, but couldn’t cause it to go into warp speed. If it were the fan itself that were the issue, it might spin too fast when it’s on, but it wouldn’t be able to turn itself on. That narrows it down to a failure in the Glowforge circuit board, probably a switching component shorted and sending too much voltage to the fan. My big concern would be that the problem might not only be affecting the fan. But I’d unplug or cut it out too, in your position, as trying to get it repaired is probably going to be quite expensive.
I don’t think that applies to brushless motors because they’re speed controlled by precise switching, yeah? Or do I have that wrong?
As far as I know the failure mode of brushless motors is ESC death and then the motor will simply not work.
I suppose it depends on the fan. The ones I have experience with only have two wires, and the controller is inside of the fan hub. If you give it higher or lower voltage, the fan goes faster or slower.
I’m sure there are ones with an external controller, and I’m ignorant of what’s in the Glowforge and too lazy to find out.
Yeah like in RC models there are multiple wires, one of which is PWM to control the speed. Lots of computer fans (which this basically is) also have a PWM speed wire.
I think the fan model is the Sunon PF92381BX-000U-S99 which is a typical 4 wire brushless fan. Power, ground, PWM, and tach sensor.