If nearly burning down my Delta printer isn’t bad enough, I also have a problem with the Cartesian printer. It has so many run-hours on it, I have worn out the bearing in the extruder cold-end cooling fan. There is probably a sleeve bearing in this axial fan and the blades are barely spinning. It is supposed to run all the time at full speed when the printer power is on. Well, it doesn’t spin full speed now. It almost stops spinning. I can count the revolutions by just watching it.
I purchased a package of two ball bearing replacement fans. One for spare. They look exactly like the original. Nothing on either fan or the original says what type of bearings. I have to assume the new ones are ball bearing because the presentation of the product on Amazon said they were (dual) ball bearing.
I bought some heat shrink tubing as I solder-spliced the wiring. That was easier than trying to install a pull apart electrical coupling.
The new fan spins very fast at the 12 volt / 0.10 amp power. I can hear it running but the sound level at a few feet is only 50db which is only 5 db over the ambient 45 db in my office. Very acceptable. I have a sound meter app in my cell phone. Good enough for this kind of measurement.
The picture shows all three fans. One of the new ones is installed. Look close (click to enlarge) and you can see the wire splices. The old fan is on edge in the middle and the new spare is flat on the bed. They cost about $7.50 each. Not a bad an expense. There is also a fair amount of dirt on the old blades. This was not unexpected as I am a very experienced HVAC engineer. We live in a dirty world.
I don’t think the dirt caused the motor to slow. Probably very light lubrication in the bearings. A failure of the lubricant from nearly 2 thousand hours of operation.