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The monitoring of the sliding bearings in shielded pumps is generally used to monitor the wear of the support bearings and the thrust bearings. The TRG gauge for detecting bearing wear operates on the following principle: A coil is installed above and below the stator coils of the canned pump (for horizontal pumps, this corresponds to positions above and below the stator shield). These two coils are connected to each other but have opposite phases. As the rotor rotates, if the “center line of the rotor” coincides with the “geometric midpoint of the two coils, which is also the midpoint of the pump bearings”, then the upper and lower coils generate voltages of equal magnitude but opposite phases; these voltages cancel each other out, resulting in no current flow, and the TRG gauge shows a reading of 0, at the lowest point in the green zone. When the bearings are worn, the center line of the rotor shifts, and the voltages generated by the upper and lower coils are no longer of equal magnitude. After certain processing, a current is generated, and the TRG pointer changes accordingly. As long as the reading remains within the green zone, the wear caused by the bearings is acceptable; the rotating rotor will not damage the shield, and the pump can continue to operate. Once the pointer enters the yellow zone, it indicates that the wear is worsening and maintenance is necessary, with the bearings needing to be replaced. If the pointer reaches the red zone, it means that the rotor has damaged the shield, and it is then necessary to disassemble the pump to check whether the shield is still intact. As can be seen from the above, the TRG table only detects radial wear of the bearing, because it is only after radial wear occurs that the rotor’s centerline shifts; the axial displacement of the rotor cannot be detected by this table. Thrust bearing wear detector, axial displacement monitor: It operates on the principle of eddy currents for detection, and consists of a measuring instrument and a magnetic probe. The measuring instrument is installed on the pump’s rear bearing body made of non-magnetic material, while the magnetic probe is attached to the shaft end screw and moves along with the rotating components. Changes in the gap between these two components reflect changes in the strength of the magnetic field detected by the measuring instrument; thus, by measuring the strength of the magnetic field, the measuring instrument can determine the axial displacement of the rotating components.