#Motors
I used some downtime to investigate this “cricket-chirp” sound I’ve been hearing from one motor. It started on my last build, before its untimely death, and continues after the move to this build. It wasn’t so bad that it was concerning, but more an issue that it masks any other noises that might end in worse problems.
At one point I slammed that motor into a rock, so it doesn’t surprise me that there’s an issue. After some investigation, there seems to be some shaft misalignment - I can see the gap between stator and rotor bell increasing and decreasing as I hand spin the bell. I figured it was rubbing somewhere.
Time to disassemble! Lucky me, found a broken winding in the process (or caused it).
I used the aspirin trick to remove the winding lacquer:
Get one tab of full strength aspirin (not tylenol, advil, etc). Get soldering iron hot and tin the tip. Press end of winding and iron tip into aspirin at the same time. Make sure to use a real fume extractor (or hold your breath) - fumes are super toxic, more than usual. After 10-20 seconds, the lacquer has melted off and the wire will come out tinned!
Worked like a charm.
Solder wire ends together, apply much too large heat shrink, and tuck into stator.
While I was at it, I figured I’d do a full battle harden with epoxy (and colloidal silica to thicken). Some of the other windings were loose and did not inspire confidence.
Isopropyl alcohol on a shop rag does a nice job of cleaning up epoxy while still wet. This was actually a lot easier and quicker than I expected, and I only had a popsicle stick and gloved fingers to apply. Maybe not entirely necessary, but the peace of mind knowing the motor is more waterproof (including sensor) is great.
After a 24hr cure, I went to work filing down the edge of the stator to solve the rubbing/noise issue. Medium file, fine file, 400 grit, 800 grit sandpaper, b/c why not.
Reassemble using the patented @b264 towel technique.
Fun fact - this wasn’t the problem and did nothing to solve my noise issue.
Plan B - blue all the things and look for contact.
I ended up blueing almost the entire stator and found nothing conclusive… but, silver lining, something happened after 3-4 rounds of reassembly that shook/smashed/moved the noise into silence. My best guess is that it may have been Flipsky’s “battle-hardening”/balancing epoxy that got dislodged and was rubbing. Either way, the noise is 90% gone.
And now I have one motor with a shiny raw aluminum “machined lip”.
A E S T H E T I C S
It was a fun learning opportunity anyway. Disassembling these motors is about as difficult as disassembling a truck. I won’t hesitate to inspect in the future.
AND color coded so future me wouldn’t have to play this game again
) and they lit up first go!
