Water Cooled Bearings

Question: Why does my motor have water cooled bearings?

Answer:

Vertical motor thrust bearings can generally be cooled by free or forced air convection over the bearing housing. In some cases, bearing losses and the resulting heat generated can be greater than the heat dissipating capability of the bearing housing. Bearing size, thrust loading and speed all affect bearing losses and the heat generated by the bearing. The cooling capability of the bearing housing is affected by ambient and/or altitude conditions. The type of lubricating oil determines the maximum temperature that can be sustained under the given bearing operating conditions. Excessively high temperature leads to oil viscosity breakdown and oxidation and can result in lubrication and bearing failure.

In order to limit bearing oil temperature to an acceptable value, auxiliary cooling means must sometimes be employed. The most common method is to insert an oil cooler into the thrust bearing oil sump. USEM's standard oil sump cooler is a self-draining copper coil, inserted into the oil bath, which requires a minimum of 4 GPM at 125 PSI maximum and a maximum inlet water temperature of 90 degrees F.

An unbalanced bridge circuit in the control can also give false readings.

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