Abstract: A motor and a rotary potentiometer, or other position sensor, running on the motor shaft are mounted in a first enclosure with an output shaft for driving a power switch open or closed. A part of the system outside the first enclosure makes use of a motor position signal from the rotary potentiometer that is processed by a microcontroller that a worker can interact with at a switch panel to set and adjust motor travel limits without needing access into the motor enclosure. The first enclosure and its components can be used for various applications, including those for either underground or pad-mounted switches, which for the latter case can have the first enclosure inside a second enclosure on a pad, and the second enclosure also contains other power and control elements of the system. A portable unit with the switch panel for travel limits can be provided.

Abstract: A motor operator with a continuity sensor has a test current injector and a voltage sensor arranged to determine if a loss of AC voltage is due to a discontinuity, such as a blown fuse, in the circuit of a transformer powering the motor operator rather than a loss of voltage from an AC power line. A line voltage detector, such as a resistive or capacitive voltage divider, can also be used with a continuity sensor to distinguish between a discontinuity in the voltage detector and a loss of line voltage. Based on the cause determined by the continuity sensor, signals are generated either to motor operate a disconnect switch or not to.