Improper assembly, poor sealing and load fatigue are all key factors leading to premature failure of motor bearings, thereby reducing their actual service life. To ensure the long-term safe operation of the motor’s active components—the stator and rotor—the service life of the motor bearings is also crucial.

Generally speaking, metal fatigue at the rolling contact surfaces is the key factor in rolling bearing failure. The service life of a rolling bearing is defined in terms of rotational speed (or the number of operating hours at a given rotational speed); within this service life, the motor bearing must not exhibit any initial fatigue damage (spalling or fracture) on any of its bearing rings or rolling elements.

As the actual service life of identical motor bearings under the same operating conditions varies, ‘rolling bearing service life’ is more accurately defined as the service life value that 90 per cent of a sufficiently large group of identical bearings should achieve or exceed under rated load. So, how can bearing service life be extended?

I. Installation and Removal

(1) Employ mechanical, hydraulic or heating methods to ensure correct and effective bearing assembly.

(2) Utilise a complete set of specialised tools and equipment based on professional engineering techniques, ensuring these tools are simple, convenient and cost-effective.

(3) Employ specialised tools and techniques for professional assembly to maximise equipment uptime.

II. Preventing Contamination

Motor bearings are high-precision components; if the bearings or lubricant come into contact with contaminants, they will be unable to operate effectively. Furthermore, as maintenance-free sealed bearings—which are pre-filled with grease—account for only a small proportion of all bearings in use, at least 15 per cent of all premature bearing failures are attributable to contamination.

III. Preventing Fatigue

(1) Overloading of equipment, as well as improper use or maintenance, can damage bearings and lead to premature failure.

(2) Monitoring systems can be used for inspection and analysis; when bearings are subject to improper maintenance or excessive stress, they will issue an ‘early warning’, thereby preventing unexpected or unplanned failures.