Bearing failure detector for electrical generator

Abstract

A bearing failure detector for an electrical generator includes a disc located within the bearing assembly near the location of the main bearings. The disc has a central opening through which the shaft extends, and the disc includes a thin, electrically conductive ring which is plated or formed as a film inside the central opening. The ring is exposed to the shaft along inside diameter of the detector disc adjacent to the periphery of the shaft, but a gap is normally provided around the shaft when the shaft is properly supported by the main bearings, so that the shaft does not contact the ring unless the bearings are significantly worn. The ring provides a closed circuit, and it is connected to a control circuit which monitors the closed circuit at all times. When the internal clearance of the main bearings has been enlarged by a predetermined amount, the ring contacts the shaft, causing the thin ring to be quickly worn away. This causes an open circuit through the detector, which is sensed by the control circuit to provide an indication that the bearings need replacement. The closed circuit in the detector provides a positive indication that the detector is operating as well as an indication of bearing function. In addition, the open circuit produced by the main bearing failure is continuous rather than intermittent and is easily sensed.