Buke servo motor - the cause of common faults in motors

1. Sweeping: Sweeping is generally caused by friction of the stator and rotor due to bearing damage, shaft bending, or improper assembly during maintenance. In the process of overhaul and assembly of the motor, all parts of the motor should be kept clean, and the assembly of end covers, bearings, etc. should be reasonable and not barbaric, otherwise the corresponding parts will be deformed and the motor will not be able to operate.

2. Bearing damage: Bearing damage is a common fault in the operation of the motor. The causes of bearing damage are:

(1) Improper bearing assembly, such as uneven knocking on the inner ring of the bearing during cold assembly, causing the shaft to be worn, resulting in the loss of interference or interference between the inner ring of the bearing and the bearing, and the phenomenon of running the inner ring, and the uneven knocking of the end cover of the motor when installing the end cover of the motor causes the end cover bearing chamber and the outer ring of the bearing to be too loose to run the outer ring. Whether running the inner ring or the outer ring, it will cause the bearing to rise sharply and burn out, especially the failure of the inner ring will cause serious wear and bending of the shaft. However, intermittent running outer ring will not cause a sharp rise in bearing temperature under normal circumstances, as long as the bearing is intact, the phenomenon of intermittent running outer ring is allowed.

(2) The bearing is replaced, and the interference amount is large or the ellipticism exceeds the standard after the nesting of the motor end cover, which causes the ball clearance to be too small or uneven, resulting in an increase in friction during bearing operation, and a sharp rise in temperature until it burns out.

(3) The bearing cavity is not cleaned or the grease is not clean. For example, the tiny rigid substances in the bearing cage are not thoroughly cleaned, and the bearing raceway is damaged during operation, resulting in excessive temperature rise and burning of the bearing.

(4) Due to the axial misalignment of the stator and rotor cores or the lack of accuracy after re-machining the shaft, the inner and outer rings of the bearing are not on the same section, which causes the temperature of the bearing to rise until it burns out after the operation of the "special force".

(5) Due to the high temperature rise of the motor body, and the bearing is not replenished in time, the bearing is short of oil or even burned. (6) Bearing damage caused by the mixing of different types of grease.

(7) There are manufacturing quality problems in the bearing itself, such as raceway rust spots, inflexible rotation, excessive clearance, cage deformation, etc.

(8) The standby machine is not running for a long time, the grease deteriorates, and the bearing is rusty and has not been overhauled.

3. Vibration: Vibration should be distinguished whether it is caused by the motor itself, or caused by poor transmission, or transmitted from the mechanical load end, and then eliminated according to the specific situation. The vibration caused by the motor itself is mostly caused by poor dynamic balance of the rotor, poor bearing, bending of the rotating shaft, or different shafts of the end cover, frame and rotor, or the uneven installation foundation of the motor, the installation is not in place, and the fasteners are loose. Vibrations create noise and also create additional loads.

4. Phase-out operation: As long as there is a phase break in the three-phase power supply, the motor will run out of phase. After the three-phase motor lacks a one-phase power supply, if it is in the stop state, it will stall (cannot start) because the resultant torque is zero. The locked-rotor current of the motor is much larger than the normal working current. Therefore, in this case, the motor will burn out if the power is turned on for too long or the power is turned on frequently for many times. When the motor in operation lacks one phase, the air gap of the motor is generated by an elliptical rotating magnetic field with a high three-phase harmonic composition, if the load torque is very small, it can still maintain operation, only the speed decreases slightly, and an abnormal sound is emitted; When the load is heavy, the running time is too long, and the motor windings will burn out.

5. Winding short circuit or grounding: winding short circuit is divided into inter-turn short circuit and interphase short circuit, interphase short circuit easily causes fuse blowing, circuit breaker tripping and even affects the upper level switch to cause system failure; An inter-turn short circuit is damaged due to poor insulation performance of the winding enameled wire; So that the interphase wire directly touches, forming a low impedance current loop, so that the inter-turn current increases and makes the wire package heat, and the whole stator winding will be overheated for a long time, and finally the winding is destroyed due to the sharp rise in heat, and the inter-turn short circuit is the biggest reason for the abnormal increase in motor temperature. The short-circuit fault can be judged by measuring the current or its DC resistance when the power supply voltage of the stator winding is reduced. The grounding fault is mostly caused by the winding insulation damage, the motor water ingress, before starting the motor, the motor insulation should be tested first, and the power can be sent to run only after it is qualified.

6. Three-phase current unbalance: The fault of three-phase current unbalance is often caused by the unbalanced external power supply voltage of the motor, and the internal reason is mainly the short circuit between the winding turns or the wrong number of coil turns or the wrong wiring when the motor is rewound and repaired.

Buke servo motor - the cause of common faults in motors

Buke servo motor - the cause of common faults in motors

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