Bearings axial thrust

These motors have a lower efficiency as a result of running in liquid, causing more liquid drag and also axial thrust bearing loss, which is also a part of the motor. However, this lower efficiency of the motor is compensated by fewer mechanical and hydraulic losses in a submersible motor-pump installation, compared to a vertical turbine pump installation. 

A paper mill was using an ANSI end suction process pump with clear water service. The motor was designed properly. The pump axial thrust bearing ran hot, failing after three months of operation. It was replaced with an identical bearing. This ran during three months and also failed. All pump components were investigated and found that they complied with the specifications. These facts eliminated the defects of materials as a cause. 

Unless otherwise specified, pump out vanes shall be used to reduce leakage back into the sump. The reduction in axial thrust caused by the pump out vanes, however, shall not be considered in sizing axial thrust bearings. 

Stage package 2, Inlet 3, Outlet 4, Axial thrust bearing 5, Radial bearings 6, Axial thrust compensation "piston". 

Stage package 2/3, Clearances at the impeller 4/5, Inlet/outlet 6, Radial bearings 7, Axial thrust bearing 8, Barrel housing 9, Mechanical shaft seals. 

Intake volume, 2100 m3/h of natural gas Suction/discharge pressure, 39/186 bar 1, Barrel housing 2, Stage housing 3, Axial thrust bearing 4, Radial bearing 5, Shaft 6, Shaft-seal (gas lubricated) 7, Axial-thrust compensation piston. 

When a bearing is subject to both radial and axial thrusts the equivalent dynamic bearing loading can be expressed by... 

The motor carries and supports any axial thrust by the pump (hydraulic or mechanical). The motor on these pumps can be fitting with precision rolling element bearings, either angular contact, spherical rollers, or pillow blocks inclined depending on the thrust load and velocit of the shaft. 

These are single row ball bearings capable of handling extreme axial or thrust loads in one single direction only. They are generally mounted in pairs to handle any opposite axial/thrust loads. 

This bearing is best suited to handle radial loads. It doesn t work well with axial/thrust loads. This bearing is popular in electric motors. 

These bearings are good handling extreme axial / thrust loads in one single direction only. 

Axial length of thrust bearing (given by manufacturer)... 

The axial transducers should have one probe sensing the shaft itself within 12 inches (305 mm) of the active surface of the thrust collar with the other probe sensing the machined surface of the thrust collar. The probes should be mounted facing in opposite directions. Temperature probes embedded in the bearings are often more useful in preventing thrust-bearing failures than... 

When designing a system for thrust bearing proteetion, it is neeessary to monitor small ehanges in rotor axial movement equal to oil film thiekness. Probe system aeeuraey and probe mounting must be earefully analyzed to minimize temperature drift. Drift from temperature ehanges ean be unae-eeptably high. 

Spherieal roller thrust bearings ean aeeommodate high axial loads. They are suitable for relatively high speeds. The raeeways, whieh are inelined toward the bearing axis, allow the bearings to aeeommodate radial loads as well. The radial load must not exeeed 55% of the axial load. 

Both top and bottom halves of the journal bearings should be inspected for misalignment wear as well as excessive in-line wear, which can occur in turbines with frequent starts. An indication of the condition of the thrust-bearings can be made by removing a small section of the turbine shaft, usually on the governor end, and axially moving or bumping the shaft. The amount of axial shaft movement will indicate the thrust clearance and, if it is found to be 0.012-0.015 inches, it can be considered normal. 

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