Shenyang Getai Hydropower Equipment Co., Ltd.

Main Failures Of Thrust Bearings Of Hydraulic Turbines

Dec. 10, 2019

Today, the supplier of Hydraulic Turbine Generator China will share with you the main faults that cause the inferential bearings of hydraulic turbines.


1. The mirror surface roughness of the bearing mirror plate is increased

Cause: Natural aging, impurities in the lubricant, such as hard particles, water, etc.

Features: The temperature of the thrust tile in the same season is significantly higher than before. there is a rattling sound in the thrust bearings when the unit starts and stops.


2.The macro unevenness of the mirror plate mirror surface increases

The macroscopic unevenness of the mirror surface of the thrust bearing mirror plate is caused by the uneven portions on the mirror surface, and these uneven portions are distributed along the rotation direction of the unit. As the rotor rotates, the bearing pads will be subjected to a periodically varying load due to the irregularities.

the reason:

(1) Structural defects. For example, the bottom of the Francis Turbine thrust head is too thin, which causes deflection under the load, making the mirror plate fixed at the bottom of the thrust head uneven.

(2) The residual deformation of the thrust head thermal sleeve on the shaft caused unevenness after the mirror plate was fixed on the bottom of the thrust head.

(3) Residual deformation of the mirror plate during installation or installation.

(4) The backing plate installed between the mirror plate and the thrust head is damaged.

Francis Turbine


3. The load distribution of thrust pads is uneven.

the reason:

(1) The initial adjustment is not good due to inadequate adjustment methods or monitoring methods, or there is a large unevenness on the mirror surface.

(2) The difference in the extrusion value of the support bolt head caused by the substandard manufacturing quality requirements.

(3) The difference in the number of pits where the support plate and the head of the support bolt are in contact.

(4) Individual support bolt thread extrusion.

(5) Cracks appear on the support plate or on the balance rod of the double-row thrust bearing, causing its strength to decrease dramatically.

(6) Part of the backing plate matching the supporting bolt is damaged.


4. The elastic fuel tank of the hydraulic prop thrust bearing loses the seal.

Reasons:

(1) The pulsation value of the thrust bearing increases. Increased pulsation value (due to the unevenness of the mirror plate mirror surface, the mirror plate mirror surface is not perpendicular to the generator axis or due to the pressure fluctuation of the water flow acting on the turbine runner) can gradually make the lock ball in the check valve compaction degree Weakened, allowing oil to leak out of the elastic tank. Increased pulsation value may also cause cracks in the elastic tank wall.

(2) Manufacturing defects of thrust bearings. Manufacturing defects easily cause cracks in the elastic fuel tank, loss of tightness, sinking the support system, and lowering the entire generator rotor.


5. The thrust head is loose.

The thrust head must have sufficient strength, stiffness and certain impact toughness, and no loosening is allowed in cooperation with the journal. However, the wear and tear caused by maintenance and operation often make the fit clearance gradually increase and loosen. Loose thrust head will seriously threaten the stability of the unit operation.


6. The thrust bearing bracket and the bracket of the tile stand collide.

If the bearing bracket and the bearing bracket collide with each other, the thrust bearing will lose its flexibility, and the dynamic pressure oil film is not easy to form between the thrust bearing and the mirror plate. The thrust bearing is prone to wear, which will cause the temperature of the bearing to rise sharply, or even burn the bearing.


The above are the main faults of the thrust bearings of hydraulic turbines introduced by Hydraulic Turbine Generator Supplier. Hope to help you.

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