Abstract: An electromagnetic operator includes first and second coils wound coaxially. An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An electromagnetic operator includes first and second coils wound coaxially. An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An electromagnetic operator includes first and second coils wound coaxially An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: An electrical contactor includes an electromagnetic operator which may be powered by either AC or DC power. For use with AC power, a rectifier circuit converts AC waveforms to DC waveforms and applies the converted power to DC one or more DC coils. The rectifier circuitry applies DC power directly to a bus. A pair of coils may be used, such as separate pickup and holding coils. The pickup coil may be de-energized after an initial phase of operation. To permit rapid release of the holding coil, a control circuit interrupts an induced current path through the coil upon removal of power from the bus.

Abstract: A movable contact assembly for contactors and similar devices includes a movable spanner or conductive element biased toward a conducting position by a biasing element. A housing partially surrounds the conductive element and the biasing element. The biasing element and exerts compressive forces against the housing and the conductive element. The assembly may be installed as a modular unit on a carrier which is displaced during operation of the contactor. The housing shields the biasing element from plasma, arcs and debris during operation of the device. Multiple conductive elements and corresponding biasing elements may be includes in each assembly.

Abstract: A circuit interrupter provides a conducting path between two conductors and interrupts the conducting path in response to overcurrent conditions in the conductors. The interrupter includes a magnetic core around which the conductors are disposed. Each conductor is electrically coupled to an arc runner and a spanner is biased into contact with the arc runners to compete a conducting path between the conductors. A secondary response mechanism is provided adjacent to the core and includes arms extending around the core and a magnetic body. In response to overcurrent conditions of a first magnitude the body of the secondary response mechanism is attracted to the core causing the arms to displace the spanner out of contact with the arc runners. In response to overcurrent conditions of a second magnitude, such as due to direct short circuits, the spanner is repelled rapidly to a non-conducting position and the secondary response mechanism is attracted to the core to hold the spanner in the non-conducting position.

Abstract: A method for interrupting electrical power between two conductors is provided, including biasing an electrically conductive element into a conducting position between two contact regions of the conductors. The contact regions are preferably portions of arc runners coupled to the conductors. The conductors surround a magnetic core that generates an electromagnetic field due to current in the conductors. The conductive element is repelled to a non-conducting position by the electromagnetic field in response to an overcurrent condition in the conductors. A secondary response mechanism is moved in response to the overcurrent condition to maintain the conductive element in the non-conducting position. For more gradually occurring overcurrent conditions, the secondary response mechanism is attracted toward the core, displacing the conductive element to the non-conducting position.

Abstract: A circuit interrupter provides a conducting path between two conductors and interrupts the conducting path in response to overcurrent conditions in the conductors. The interrupter includes a magnetic core around which the conductors are disposed. Each conductor is electrically coupled to an arc runner and a spanner is biased into contact with the arc runners to compete a conducting path between the conductors. A secondary response mechanism is provided adjacent to the core and includes arms extending around the core and a magnetic body. In response to overcurrent conditions of a first magnitude the body of the secondary response mechanism is attracted to the core causing the arms to displace the spanner out of contact with the arc runners. In response to overcurrent conditions of a second magnitude, such as due to direct short circuits, the spanner is repelled rapidly to a non-conducting position and the secondary response mechanism is attracted to the core to hold the spanner in the non-conducting position.

Abstract: A snow chain traction kit for the drive wheels of a wheelchair, the kit including a number of pairs of attachment strips for each wheel and a traction strap for each pair of strips, each of the straps having a plurality of chains for providing traction on ice or snow and each pair of strips being mounted on opposite sides of the wheels, with the straps wrapped around the tire and being attached to one pair of strips.

Abstract: A conversion kit for connecting a friction drive system for a motorized wheelchair to a positive drive system which includes a cog wheel, a strip of metallic material having a number of cogs stamped at equally spaced intervals and a belt having internal cogs for matingly engaging the cog wheel and metallic strip and the method of conversion.