Abstract: A circuit and method for controlling a voltage applied to a coil to actuate electromechanical relays or contactors. The strength of a magnetic field operating the coil is a function of the product of the number of turns of the coil wire and the magnitude of current, in amperes, passing through the coil wire. An adjustable voltage regulator provides a regulated voltage as an output to a first terminal of a coil to energize the coil based on the temperature of the coil as sensed by a temperature sensing device located proximate the coil. The regulated voltage is controlled based on the sensed coil temperature to consistently provide a current of optimal magnitude to actuate the coil at the sensed temperature. A transient voltage suppression circuit may be used with the coil to suppress back electromotive force generated currents and voltages when the coil is de-energized.

Abstract: A contactor includes a plurality of switches mechanically coupled to an actuator. The actuator is moveable between operational and tripped positions. Switches that are closed in the operational position are open in the tripped position, and vice versa. The actuator extends through a coil as a core. The coil moves the actuator when an input signal is applied to the coil. A first input circuit receives a power-up input signal to transition the contactor from a tripped position to an operational position. A second input circuit receives a trip signal to transition the contactor from the operational position to the tripped position. First and second switches, coupled to respective first and second ends of the coil, reverse the polarity of the coil each occurrence of the actuator being actuated in preparation for the coil to be energized and magnetically polarized in an opposite direction during a next subsequent actuation.

Abstract: A circuit and method for controlling a voltage applied to a coil to actuate electromechanical relays or contactors. The strength of a magnetic field operating the coil is a function of the product of the number of turns of the coil wire and the magnitude of current, in amperes, passing through the coil wire. An adjustable voltage regulator provides a regulated voltage as an output to a first terminal of a coil to energize the coil based on the temperature of the coil as sensed by a temperature sensing device located proximate the coil. The regulated voltage is controlled based on the sensed coil temperature to consistently provide a current of optimal magnitude to actuate the coil at the sensed temperature. A transient voltage suppression circuit may be used with the coil to suppress back electromotive force generated currents and voltages when the coil is de-energized.

Abstract: A contactor includes a plurality of switches mechanically coupled to an actuator. The actuator is moveable between operational and tripped positions. Switches that are closed in the operational position are open in the tripped position, and vice versa. The actuator extends through a coil as a core. The coil moves the actuator when an input signal is applied to the coil. A first input circuit receives a power-up input signal to transition the contactor from a tripped position to an operational position. A second input circuit receives a trip signal to transition the contactor from the operational position to the tripped position. First and second switches, coupled to respective first and second ends of the coil, reverse the polarity of the coil each occurrence of the actuator being actuated in preparation for the coil to be energized and magnetically polarized in an opposite direction during a next subsequent actuation.