Servo control using ferromagnetic core material and electrical windings is based on monitoring of winding currents and voltages and inference of: magnetic flux, a force indication; and a magnetic gap, a position indication. The third order nonlinear servo control is split into nested control loops: a fast non-linear first order inner loop (1636) causing flux to track a target by varying a voltage output; and a slower almost linear second-order outer loop (1650, 1670, 1680) causing magnetic gap to track a target by controlling the flux target of the inner loop.

System and method for servo control of nonlinear electromagnetic actuators

In a power distribution system, synchronizing switchgear operations with an AC voltage or current waveform can be accomplished more precisely with a closed-loop feedback, microprocessor-based motion control design. By employing a closed-loop feedback, microprocessor-based design, switchgear contact position and velocity can monitored and optimized in real-time during a switching operation, thereby assuring a more accurate switching operation. Moreover, the closed-loop feedback design intrinsically compensates for the affects of such things as ambient temperature, AC waveform fluctuations, and changes in the physical condition of the switchgear. The closed-loop position feedback design is also capable of optimizing various transfer function parameters associated with the closed-loop feedback process, both during and subsequent to a switching operation, to further assure that switching operations are more accurately synchronized with the AC voltage or current waveforms.

Electrical switchgear with synchronous control system and actuator

A solenoid driver (10) capable of detecting the operational status of a solenoid (12) including the position of an armature within a solenoid coil and an operational method. The solenoid driver (10) generates a first solenoid current within the solenoid (12) and measures a first decay time t1. The first solenoid current is insufficient to pull the armature into the coil of the solenoid (12). A comparator circuit (22) continuously monitors the solenoid current and initiates a timer within a counter circuit (34) to compute the first current decay time. A second solenoid current is generated within the solenoid (12) that is sufficient to pull the armature into the coil of the solenoid (12). The second solenoid current is turned off and a second decay time t2 is measured. The decay times are stored in storage registers (R1, R2) within a controller (36). The controller (36) compares the measured decay times with stored values and outputs the armature position information over a communications bus (34).

Solenoid driver and method for determining solenoid operational status

A current interrupter (4) includes a current interrupting device (4) having at least one movable contact (71); an actuator (8) coupled to the movable contact (71) of the current interrupter (4); a feedback sensor (14) for monitoring movement of the actuator (8); and a control system (12) coupled to the feedback sensor (14) so as to receive information from the feedback sensor (14) concerning the movement of the actuator (8) and for controlling movement of the actuator (8) based on the information. The interrupter (4) further includes a memory (202) for storing a desired motion profile of the actuator (8); and a microprocessor (202) for comparing the movement of the actuator (8) with the desired motion profile and controlling movement of the actuator (8) based also on a comparison of the movement of the actuator (8) with the desired motion profile. The interrupter (4) further includes a sensor (204) for sensing a waveform of a voltage in a line to be interrupted and providing information concerning the voltage waveform to the control system (12); wherein the control system (12) controls the movement of the actuator (8) based also on the information concerning the voltage waveform.

Control method and device for a switchgear actuator

An under voltage trip device for low and medium voltage breakers, a first power supply receives unregulated power from a control voltage supply, which is rectified and regulated with portions of the power supply monitored by a processor. The output of the first power supply is supplied to a second power supply which allows pulsing modulating power to be supplied to a solenoid connected thereto. The current supplied to the solenoid is measured so as to represent the solenoid armature position which is measured and calculated by a processor and stored therein as well as being compared to stored values, thereby determining solenoid armature position and predicting or warning of solenoid failure. Connected to the second power supply is a third power supply which operates in a voltage regulator supply mode and a switcher mode during start-up and continuous running operation respectively, such mode being controlled by the processor. Switches are connected to the processor with the result that multiple control voltage sources may be selected while the position and condition of the solenoid armature and coil are determined. Further, the solenoid is pulsed with higher than rated voltages in order to firmly lock in the solenoid and to delay its decay during an under-voltage condition from the control power. Further, the power supply circuit in cooperation with the DIP switches and the processor allows for adjustment for the delay time and pick-up or drop-out points with respect to the control voltage in order to determine operation of the solenoid.

Trip device for an electric powered trip unit

An electrical contactor has first and second contacts movably mounted to engage for achieving continuity in an electrical circuit, via an electromagnet and armature defining a magnetic circuit with an air gap that closes in a first position of the contactor and opens in a second position of the contactor. A controller switches an alternating current voltage to the coil of the electromagnet during a timed portion of each AC half cycle, and senses the current level in the coil in a feedback loop. The controller adjusts the voltage-on time to achieve a predetermined average current as needed for accelerating the armature or coasting during a closing operation, for holding the armature in place when closed, etc. In order to sense whether the contactor is presently open or closed, the controller monitors and stores the phase angle between the previous voltage zero crossing and the time of voltage turn-on. When the inductance of the magnetic circuit including the electromagnet and armature changes rapidly due to opening or closing of the air gap between them, the controller detects a corresponding variation in the phase angle. The controller is preferably a microprocessor, programmed to normalize the phase angle over a range of coil drive voltages. The microprocessors of a number of such contactors can communicate in order to effect coordinated operations.

Electronic interlock for electromagnetic contactor

Elektronische Zustandsanzeige für elektromagnetisches Schaltschütz

Cet appareil comprend un electro-aimant (22) comportant une bobine (23) et une armature (24) mobile par rapport a la bobine lors de l'application d'un courant d'excitation a la bobine, l'electro-aimant et l'armature definissant un circuit magnetique comportant un entrefer variable; un dispositif de detection (72) pouvant fonctionner de maniere a surveiller au moins un courant dans la bobine et/ou une tension appliquee a cette bobine; et un circuit de commande (30) couple au dispositif de detection, ce circuit de commande pouvant fonctionner de maniere a detecter une variation dans ledit courant et/ou ladite tension appliquee a la bobine, cette variation ayant lieu en fonction d'une variation dans l'inductance du circuit magnetique par suite d'une augmentation et d'une reduction de l'entrefer. Applications: entre autres demarreurs de moteurs.

Parker A. Bollinger

Papers

Electronic interlock for electromagnetic contactor

Elektronische Zustandsanzeige für elektromagnetisches Schaltschütz

Appareil de commutation électromagnétique comprenant un système électronique interne de détection d'ouverture et de fermeture des contacts.

Electromagnetic arrangement suitable for use as an electromagnetic contactor interlock