AX-4008M-620KV Brushless Outrunner Motor 4~5S (CCW)

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price unworthy of it. Bad QC. Rather, it is recommended to purchase a Multistar motor.

Jan 15, 2018

This 4 motor is a problem with the bearing anchorage and motor shaft.
1. This issue applies to all four motors.
This is clearly seen as a QC problem and design flaw for bearings in motor production. A good motor will not be able to break away the bearings in the bearing slots. good motor is not hold the bearing by use glue and inserting a tape into the clearance of the bearing.
- Obviously all four motors had bearing anchorages, but the bearings were held loosely using tape and a small amount of glue.
So, serious problem has occurred with a slight impact (landing, etc.) and the bearings being dislodged by the lifting force of the propellers when flying.
The bearings were held loosely in place by adhesive and tape and were released into position, By constant shock and propeller lifting force allowing the bearing to move into the slot that should have been properly fitted.
However, after bearing is properly secured to the slot, the stator is 3mm lifting became a deadly phenomenon.
2. Motor shaft problem.
QC of the motor seems to be uncertain. because the other three motors have problems with the bearings, but the shaft is not a problem.
One of the four motors had a defective motor shaft, with a defective bearing.
The shaft fixing screw was loosened and a large clearance was generated so that the motor can shake.
As a result, I tried to repair these four motors themselves, but the condition still did not improve.