One Motor is Slow to Rev Up.

[stuka75]

My P34K is 1.5 yo now and a few times I"ve noticed that one motor is slow to rev up than the other three. As motors start one will hesitate before reaching rev speed of the others. It almost gives the impression that the rotor blade is loose and is tightening on with power, but all props were put on snugly. Once the ac has warmed up further start ups are right in sync. The ac has flown flawlessly throughout.
An ESC timing issue, otherwise?
Thanks.

 

[With The Birds]

Timing issue? If an ESC detects a motor isn’t synced with the line frequency there will be an error reported. How do you know the motor is spinning slower??

 

[stuka75]

Timing issue? If an ESC detects a motor isn’t synced with the line frequency there will be an error reported. How do you know the motor is spinning slower??

You can see it visually. There is a momentary pause on startup where blade appears to be spinning backwards, then revs up to sync with others. Blades are definitely on tight prior to takeoff.
Where would this error be reported?
Thanks

 

[stuka75]

I watched again after a cold start and it appears to be a slow spin up compare to other motors. I believe its actually is a slight pause giving appearance of loose prop spinning on. Again subsequent startups and flights (same battery within minutes of each other) the motors startup in sync.

 

[epicdoom]

that's an odd happening Brother. I would think the only real way to test to see if its a motor or something else would be to swap out that motor or tap its leads and watch for the power up on a DVM my first guess would be a motor problem, but it could be something as small as a Fet gating slower then it did when new.