Abstract: A logic controller formed by self-contained device modules plugged onto a DIN rail and onto a backplane contained in the DIN rail, the modules variously comprising a power supply, a logic control, I/O devices and gateways, each I/O device having microprocessor power, and the modules having a sliding lock movable into position adjacent DIN-rail-engaging flexible tabs to block deflection of the tabs and removal of the module from the DIN rail.

Abstract: A system and method for preventing contact weld under various fault current conditions is disclosed. The system includes a contactor having stationary and movable contacts biased towards each other and switchable between an open and closed position. Energization of an electromagnetic coil engages the contacts creating an electric path for current flow through the contactor. Pulse width modulation is used to lower the power to the coil and maintain the contacts in the closed position. The contactor is equipped with safeguards to prevent contact welding. Under low fault currents, welding is prevented by contact material composition. Under intermediate fault currents, the contacts are blown open and remain open using magnetic components until the arc dissipates and the contacts have cooled sufficiently. Under high fault currents, the arrangement causes the contacts to blow open and separate the armature from the coil preventing re-engagement of the contacts until the coil is energized again.

Abstract: Molded case electric power switches such as circuit breakers, disconnects and transfer switches have an energy storage spring which rotates a cam assembly to close and initiate opening of the switch contacts. The cam assembly includes a drive cam with a cam lobe which engages a drive cam follower on the moving contact assembly. Due to space limitations, the cam assembly is positioned so that the drive cam follower initially moves toward the cam assembly during closing. To accommodate for this, the cam lobe has a generally radial leading edge to prevent binding of the drive cam follower. A single latch mechanism latches the cam assembly in a spring charged position and in a closed position. A Y-shaped latch member has one leg which is engaged by a latch, a second leg which engages stops on the drive cam at the charged position and the closed position, and a third leg which sequentially engages the stops to reset the latch mechanism.

Abstract: A motor control circuit for a power tool includes a function switch which has a first battery contact, a speed control contact, a bypass contact and, a second battery contact connected in that order in a line. The function switch also has a movable contact which sequentially connects the first battery contact to the bypass contact, the speed control contact to the second battery contact, and the bypass contact to the second battery contact. A solid state switch has conduction path connecting the speed control contact to the second motor terminal wherein the conduction path is controlled in response to an oscillator signal.