Sturman Industries, Inc.

Christopher C North

Jeffrey A Stewart

Position sensors and methods having a coil, a magnetic target movable into greater and lesser proximity to the coil responsive to the position to be sensed, and circuitry responsive to an inductance of the coil to provided a measure of the proximity of the magnetic target to the coil. Various embodiments are disclosed, including embodiments having improved sensitivity and shielding from stray fields and for shielding from magnetic fields generated by the coil excitation.

Position sensors and methods

A method of actuator coil temperature control for actuators that are not continuously operated, wherein when an actuation current is not being applied to the actuator coil, a) sensing a parameter indicative of the resistance of the actuator coil as an indication of the temperature of the actuator coil, b) if the sensed parameter indicates the temperature of the actuator coil is below a first predetermined limit, then initiating a series of successive actuation current pulses to the actuator coil, each actuation current pulse being terminated before actuation of the actuator occurs, and c) periodically repeating a) and b).

Control valve coil temperature controller

Pulsed-energy controllers and methods of operation thereof for driving inductive loads such as the actuator coil or coils of electromechanical actuators. The controllers utilize an inductor through which an initial current is established through a first circuit. The inductor is then switched across the actuator coil or other inductive load in a second circuit and the first circuit is opened. The back EMF of the inductor, limited by a high voltage protective device, causes a rapid rise in the current through the actuator coil, the rise being much faster than could be achieved by merely coupling the supply voltage, as used to establish the current in the inductor, directly to the actuator coil. By proper selection of the controller circuit and its parameters, the initial rapid current rise may continue to a current higher than a steady state current, after which the current will decrease to or toward the lower steady state current until the current pulse is terminated. Various embodiments are disclosed.

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Woodland Park, CO, United States of America

Christopher C North