Abstract: An axial position detection circuit detects the axial position of a rotor from the difference in voltages generated at axial position detection coils disposed at both ends in the axial direction of a stator of a canned motor. An axial zero point adjustment circuit uses a voltage supply, which varies proportionately with the power supply voltage of the canned motor, as a bias power supply to adjust the voltage difference of the axial position detection coils to zero when the rotor is at a reference position in the axial direction. Even if the power supply voltage of the canned motor varies, since the bias power supply of the axial zero point adjustment circuit varies in likewise manner, the zero point adjustment by the axial zero point adjustment circuit is not affected and axial bearing wear detection of high precision is enabled.

Abstract: An axial position detection circuit detects the axial position of a rotor from the difference in voltages generated at axial position detection coils disposed at both ends in the axial direction of a stator of a canned motor. An axial zero point adjustment circuit uses a voltage supply, which varies proportionately with the power supply voltage of the canned motor, as a bias power supply to adjust the voltage difference of the axial position detection coils to zero when the rotor is at a reference position in the axial direction. Even if the power supply voltage of the canned motor varies, since the bias power supply of the axial zero point adjustment circuit varies in likewise manner, the zero point adjustment by the axial zero point adjustment circuit is not affected and axial bearing wear detection of high precision is enabled.

Abstract: Axial bearing wear in a motor is determined by differencing signals from special coils in the two ends of the motor stator. The signals on the two coils vary in opposite directions with axial displacement of the motor rotor. A dead zone circuit suppresses output when the axial displacement of the rotor is within the normal range of play for the rotor of the particular motor. When the axial displacement exceeds the normal range, the output actuates an indicator in relation to the magnitude of the displacement in excess of the normal range. Sequential LED indicators indicate both magnitude and direction of excess displacement. An analog meter is also disclosed which indicates only the magnitude of the excess displacement.

Abstract: Axial bearing wear in a motor is determined by differencing signals from special coils in the two ends of the motor stator. The signals on the two coils vary in opposite directions with axial displacement of the motor rotor. A dead zone circuit suppresses output when the axial displacement of the rotor is within the normal range of play for the rotor of the particular motor. When the axial displacement exceeds the normal range, the output actuates an indicator in relation to the magnitude of the displacement in excess of the normal range. Sequential LED indicators indicate both magnitude and direction of excess displacement. An analog meter is also disclosed which indicates only the magnitude of the excess displacement.

Abstract: A rotation-direction signal inclusion device which outputs the larger of a rotation-direction signal and a bearing-wear signal includes a limiter circuit which limits, or "clips", a bearing-wear signal when a short-circuit wire connected across the limiter circuit is opened. When the short-circuit wire is intact, the bearing-wear signal bypasses the limiter circuit and the bearing-wear signal is not limited.