Eaton Corporation

Thomas A Wilsdon

John Joseph Shea

James E Hansen

James Alan Bauer

Henry Anthony Wehrli, Iii

Denis A Mueller

Michael R Scharnick

John R Wilson

A switching filter is disclosed for discriminating false control signals from actual control signals. The switching filter is particularly useful on a high impedance input, such as that of a motor controller. The filter is designed to compensate for capacitive, inductive, and/or resistive coupling between extended control lines that are run in parallel with other power lines. A low impedance is switched into the otherwise high impedance control line input for a brief instant to dissipate and phase shift false control signals to prevent the controller from interpreting the false signals as actual control signals. The filter includes a first resistor connectable to sense a presence of a possible false control signal, and a second resistor, having much lower resistance than the first resistor, connected in a path between the control line input and circuit common. A switch is provided in series with the second resistor to open and close the path between the control line input and circuit common in response to the possible false control signal. A timer is activated by a presence of a possible false control signal on the first resistor and activates the switch to provide a low shunting resistance across the control line to common for the brief period. The low shunting resistance not only dissipates the amplitude of any false signals, but also phase shifts the signals such that the controller cannot recognize multiple, successive false signals as a true control signal.

Switching filter producing a low impedance control input on a high

A contactor for selectively connecting at least one alternating current (AC) power line to a load and sourcing an AC current having periodic zero crossings includes a fixed contact; a movable contact mechanism; an operating mechanism for engaging and moving the movable contact to an open position in the absence of a closing signal; and a synchronized opening mechanism for disabling the closing signal in synchronization with a zero crossing of the AC current. The operating mechanism is disengaged from the movable contact, in a closed position, by a gap having a predetermined length in order that the contacts are separated at the AC current zero crossing. The contactor may further include a vacuum bottle for enclosing the fixed and movable contact therein. The movable contact may be carried within the vacuum bottle by a bottle stem which protrudes from the bottle and has a surface for engagement by the operating mechanism. The operating mechanism may include a crossbar and an arm having a surface for engaging and moving the bottle stem. The gap may be an overtravel gap between the arm and the bottle stem. The length of the gap may be determined by a length of the bottle stem or, alternatively, by a thickness of the contacts. The synchronized opening mechanism may include an electromagnet which has a coil which is energized in order to generate a closing current and which is deenergized in order to disable the closing current in synchronization with the zero crossing of the AC current. The length of the gap may be determined from a closing velocity of the arm multiplied by a period of the AC current zero crossings. The length of the gap may also be determined from a breakpoint in a plot of an overtravel gap versus contactor contact breaking cycle operations.

Synchronous contactor

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Pewaukee, WI, United States of America

Thomas A Wilsdon