Dumb question, I missed a turn so now what?

[Foam Addict]

Hey all,
I rewound another CF 2822 for my UF-22 (don't ask), and discovered after several tests that I had missed a turn on one tooth, I know that the DT-750 has some "creative" turn counts and still works fine, so what problems could this missed turn cause?

 

[lonewolf7717]

Thinks guys that custom turn their motors are at a level of badassery that I dare not approach. Sorry can't help but interested to know the response from those in the know.

 

[lonewolf7717]

My answer: you will rip open a massive hole in time and space teleporting you to another dimension where foamboard does not exist.....ok ok ok serious time now....someone solve this man "perceived" problem!!

 

[Craftydan]

Ever had a cylinder on an engine that regularly missed?

yeah, probably not that bad, but I would expect the weak phase to be constanlty accellerating/decelerating and pulling unevenly on the motor every third phase, so expect a vibe that tracks with the RPM. Will this be enough to rip a part the motor? dunno -- it will put a bit of strain on the glue joint between the magnets and the bell, and that phase will be acting on the bell asymetrically which will likely strain the berrings . . . but enough to break something quickly?

Suppose how bad it will be depends on how many turns per pole -- if you missed one out of 4, that's bad, but one out of 12?

 

[Foam Addict]

Thanks for the help Dan, I missed the wind on one tooth out of 6. LRK wind.
I couldn't find a good explanation, other than that I just boosted the KV a little.
Btw, this motor survived 2 flights with a badly bent shaft, so it can survive until I rewind that phase.

 

[Craftydan]

If it would keep you out of the air, proceed . . . with the typical caution due any flying cuisanart (although Prop-in-Slots are generally pretty safe). I'm curious how much extra vibe you catch from it, but the vibe off the wash on the back of the slot is usually pretty bad on it's own.

Also kinda surprised the KV went up when the effective turn count dropped a smidgon. Seems reverse of what I'd expect.

BTW, keep in mind that shortened leg will have less resistance than the other two, so try to stay clear of the ESC's max current -- one pair of FETs will probably be passing ~15% more current in that phase.

 

[Foam Addict]

Hmm, evidently a lot.
The motor cooked after 30 sec of flight. After unwinding it, I found that all phases were wound in the correct directions, and that one phase had not burned. This phase was a standard phase, wound with 9t.
I'm suspecting one of my ESCs as the culprit because the exact same thing happened to this motor on the previous rewind with this ESC, but had flown 8 flights with the hk30a ESC without a problem on that same wind.