Wind turbine bearing flushing

Plant / Facility:

  • Wind energy
  • Height of rotor axis above ground level: 78 m
  • Wind turbine: GAMESA type G90
  • Turbine power: 2 MW
  • Rotor diameter: 90 m

description of the customer’s problem

The main bearings of the turbine rotor were filled with grease, which (according to the information provided by the ordering party), had been in use since the beginning of the commissioning of the wind farm in 2012. During operation, relubrication was carried out according to the approved schedule. Laboratory analysis of the samples taken indicated the need to replace the lubricant, both in the front and rear bearings, due to numerous contaminants and grease sintering.

proposed solution

Due to the impossibility of completely removing the grease by mechanical means, a service of flushing bearings with flushing oil was proposed.
The implementation is planned in two stages: Stage I front bearing, Stage II rear bearing, using a bearing flushing unit with a pneumatic diaphragm pump along with oil hoses and fittings (couplings, valves). Bearing flushing is to take place with the rotor running at a set generator speed between 200 and 500 rpm.
The plan was to flush each bearing three times with flushing oil, flush once with viscosity oil, and then drain the system and inject new grease.

course of implementation


1 The implementation of the front and rear bearing flushing was performed separately, due to the inability to stop the wind turbine for too long.

Duration of service

2. the duration of the service is 2x 2 working days each or 3 working days with the assumptions of min. 10 working hours.

Required employees

3. the number of employees required to carry out the service is 2 service technicians and 1 supervisor carrying out the work together with the service technicians.

Rinsing process

4. due to the inability to open the bearings on both sides, it is not possible to fully clean the chamber mechanically. Grease deposited in the space between the bearing barrels was removed during the flushing process.

Wire replacement

5. to safely perform the operation of removing grease from the bearing space, it is recommended to replace the rigid cables of the rotor lock with flexible cables. Flexible hoses will allow you to change the position of the interlock pump without depriving the system of functionality.

As part of the cleaning process, we recommended replacing the rigid rotor interlock cables with flexible ones.

This will increase the safety of servicing operations and allow the interlock pump to be repositioned without depriving the system of functionality.

result achieved:

After the process of flushing the bearings and filling the bearings with new grease, the turbine was returned to normal operation.
A sample of bearing grease was taken and subjected to laboratory analysis, confirming the effectiveness of the implementation.


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