So at a certain rpm, I get that crazy wrrrt motor sound and after some small rpm range it goes away
This started happening on the first warmer days this year and the magnets are holding up really well as I have had this issue for 2 months and I finally now opened up the motor.
Magnets are battle hardened so idk how they menaged to go to shit…
This is literally my 5th or 6th Maytech gone to shit after less than 1000km…
Cant even imagine how often others break
When I put in the shaft only only a few mill in the bearing and spin, it seems to be perfectly true, also dont see a reason why a bit bent shaft would cause this issue when the motor spins alone…
You could sand with a fine sand paper parallel to the laminations
The stator is made in layers insulated from one anotherto reduce the induced current loop, Eddie current loses, when you file them there is a big chance they are connected again
is there excessive play when you wiggle the motor shaft against the can?
Is there excessive play when you wiggle the can or the shaft against the bearings? (can you make the can rub?)
just asking questions I’d ask myself. I’m curious about motor failures.
The can is supported by the shaft, but only at one end. Basically it’s one big lever, so any undue force (hard drop, impact, big rocks, whatever) can bend the shaft, or the bore in the can that the shaft is pressed into. Have a look at this picture, lovingly drawn in MSPaint.
The only place the can and magnets are supported is at the red arrow. So if the shaft is bent near the red arrow, or the hole the shaft is pressed into is wobbled out, then the can will not run true.
You can also see that a very tiny bend or deviation there, can result in a significant deviation at the far end of the can.
It’s an inherent design flaw in most of the motors we use, since they are descended from motors designed for RC airplanes, where they don’t see these kinds of lateral forces.
The only motors that are immune from this weakness are inrunners, or outrunners with a third bearing to support the can’s other end such as Hobbyking Sk3 and SK8, and a few others that don’t spring readily to mind.
That sound could just be a single loose winding wire resonating at certain pitches. Covering it with epoxy (sometimes called battle hardening) could rid the noise at the detriment of not cooling as efficiently.
That may not be what’s wrong, but it’s definitely a possibility. If it is that, then eventually it could cause failure after prolonged use. But this is a lot of speculation.
Like I mentioned earlier, it’s a design flaw with pretty much all esk8 outrunner motors, with a couple notable exceptions that I mentioned, like the SK3 and SK8 and a couple others I don’t remember.
ALL other outrunner esk8 motors have this weakness. Torqueboards, APS, Maytech, Flipsky, all of them.
6374 and 6380 tend to have more problems than 6355s, because the cans are longer, and thus more leverage.
Motors with 10mm or 12mm shafts tend to be much better than ones with 8mm shafts because the
thicker shafts are stiffer and more resistant to getting bent.
But even a 6355 with a 12mm shaft is not 100% immune.
I think all cans that do not have a bearing on the end of the can like those 6396 motors run the risk. However those motors overheat like crazy, maybe because they are sealed off too much?
Also about 5 bearings on the same axle, thats not really a great idea. More than two bearings on a axle cause more bearing wear because they are never totally the same, thus having one bearing spin not completely true.
