US 4,584,865 AGranted

Device and method for testing for motor bearing wear

AssigneeLawrence Pump and Engine Company

InventorClement Hutchins

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Abstract

A canned motor pump has a bearing wear sensing device comprising a pair of ring elements having opposing surfaces. The outer element is mounted fixed with respect to the stator and the inner element is mounted for rotation with the rotor. The outer, fixed element is coated with polytetrafluoroethylene. An ohmmeter measures the resistance between the elements through the coating. As the motor bearings wear, displacement of the rotating element causes wear of the coating which reduces its thickness and decreases the resistance between the sensing elements through the coating. One conductor of the ohmmeter is connected directly to the outer, fixed element, and the other ohmmeter conductor is connected through the conductive bearings to the rotating element. Thus, the ohmmeter can dynamically measure the motor bearing wear.

Claims11

Dependent claims

In a motor having a stator, means for supporting conductive bearings fixed with respect to the stator, and a rotor supported by the bearings for rotation about an axis, a device for testing for bearing wear comprising:

a conductive ring element fixed with respect to the stator and co-axial with the rotor axis;
a conductive rotary ring element co-axial with and attached to and supported for rotation with the rotor;
one of the ring elements having an internal surface and the other ring element having an external surface, the internal and external surfaces facing each other closely, one of said facing surfaces being coated with a resistive coating;
and
means for dynamically measuring the resistance between the ring elements through the resistive coating, said means being connected between the fixed element through an electrical path including the bearings to the rotary element;
whereby wear of the bearings causes wear of the coating and the resistance measuring means dynamically indicates a decreased resistance between the rings through the coating as a measure of the degree of bearing wear.

3 more elements

Dependencies are inferred from the claim text.