Method of monitoring a contactor

摘要

The method comprises operating the contactor from an actuated condition to an unactuated condition by de-energizing a coil of the contactor, applying a voltage of short duration across the coil of the contactor while maintaining the contactor in the unactuated condition, and determining the position of the armature of the contactor relative to the stator while the contactor is in the unactuated condition by monitoring a characteristic of voltage across the coil of the contactor. A varying voltage is transmitted to the coupler which transmits information to a controller. The frequency of the output from the coupler corresponds to the frequency at which the phototransistor is changed between the conducting and non-conducting conditions. The controller determines whether the frequency of the output from the coupler corresponds to the intended position of the armature of the contactor or to an unintended position by comparing the frequency of the output from the coupler to known frequencies for various positions of the armature.