bearing failure frequently

As suggested to give a reply some more details are required.Like Direct or Belt driven?

Coupling type, Driven equipment Mounting of the motor etc

He means what KIND of coupling. Rigid? Flexible? and if so how flexible? Rigid couplings that are even SLIGHTLY misaligned will chew through bearings faster than a beaver can chew through logs.

If these are conical roller or angular contact ball bearings, also look at the bearing pre-load. too high a pre-load will cause these units to fail prematurely as well.

Also look at balance and vibration issues, if the load is out of balance the resultant vibrations can sometimes hit the resonant frequency of the assembly and go into amplification which will pound the hell out of the bearings.

• Excess dirt in the area where the motor is mounted.
• Standby motors can also suffer where they are on the same skid frame where the duty motor is vibrating.
• Etc.

Did you check up failed bearings or asked any bearing expert for opinion?

This is usually the best way to start. There are telltale signs of the reason.

In motor/generators there is one more possible reason, electrical arcing due to leaked rotor currents.