How to Estimate Babbitt Bearing Temperature

Once you have selected the correct thrust bearing style and size, you may want to estimate the babbitt temperature of the operating bearing. This is a good design practice when:

• Bearing loading exceeds 400PSI (2.8 Mpa)
• Collar surface speed exceeds 15,000 feet per minute (76.2 m/s)
• Inlet oil temperature exceeds 120°F (50°C) or
• Specifications limit maximum allowable temperature

To estimate the babbitt temperature at the recommended 75/75 position, the graph on this page illustrates performance comparisons of different types at 3.0 MPa loading. If the temperature exceeds 265°F (130°C), you may be able to reduce temperatures to a more acceptable level by substituting chrome-copper-backed shoe or offset-pivot steel shoes for plain steel shoes. Consult the graph below to determine if this is the case. For those applications where the babbitt temperature still exceeds 265°F (130°C), contact Kingsbury's Engineering Department for additional suggestions, or for details on different load ratings.

Using the Babbitt Temperature Curves

Our experimental work with a variety of shoe designs and materials indicates that the comparison below can be applied with reasonable accuracy to the J, B, E, and S styles of bearings.

The curves are based upon tests performed in our Research and Development Center using 10.5" diameter, six and eight shoe bearings, operated with light turbine oil [150 SSU @ 100°F; 32cSt @ 40°C] supplied at 115°F (46°C).

All measurements were taken at the 75/75 position, as indicated on the drawing below.