Abstract: A device with power factor correction for converting three-phase alternating-current power into direct-current power includes a DC to DC power converter, a first set of three diodes, a second set of three diodes, an input capacitor connected to the power converter, an input resistor disposed between the second set of diodes and the power converter, and a differential amplifier connected to the second set of diodes, a non-inverting input connected to the power converter, a negative power voltage connected to the power converter, a positive power voltage connected to the power converter, and an output connected to the power converter driving the power converter toward the sensed current at the inverting input and the non-inverting input being proportional to the voltage across the positive power voltage and negative power voltage.

Abstract: A device for selectively controlling access to a plurality of secure areas includes a driver circuit including a plurality of drivers, and a plurality of access modules each assigned to a corresponding secure area of the plurality of secure areas. Each access module is operatively coupled to at least one actuator operative to grant or deny access to the corresponding secure area. Unused drivers provided to a first access module of the plurality of access modules are cascaded to a second access module of the plurality of access modules.

Abstract: A device for selectively controlling access to a plurality of secure areas includes a driver circuit including a plurality of drivers, and a plurality of access modules each assigned to a corresponding secure area of the plurality of secure areas. Each access module is operatively coupled to at least one actuator operative to grant or deny access to the corresponding secure area. Unused drivers provided to a first access module of the plurality of access modules are cascaded to a second access module of the plurality of access modules.

Abstract: A device for selectively controlling access to a plurality of secure areas includes a driver circuit including a plurality of drivers, and a plurality of access modules each assigned to a corresponding secure area of the plurality of secure areas. Each access module is operatively coupled to at least one actuator operative to grant or deny access to the corresponding secure area. Unused drivers provided to a first access module of the plurality of access modules are cascaded to a second access module of the plurality of access modules.

Abstract: A device for selectively controlling access to a plurality of secure areas includes a driver circuit including a plurality of drivers, and a plurality of access modules each assigned to a corresponding secure area of the plurality of secure areas. Each access module is operatively coupled to at least one actuator operative to grant or deny access to the corresponding secure area. Unused drivers provided to a first access module of the plurality of access modules are cascaded to a second access module of the plurality of access modules.

Abstract: A power distribution system is provided comprising a power regulator, a battery circuit, and a battery monitoring system. The power converter is provided for converting AC power to DC power and for providing DC power to a load. The battery circuit is coupled to the power regulator and the load and is operable to recharge by receiving DC power from the power regulator. The battery circuit is also operable to supply DC power to the load when there is an interruption of power from the load. The battery monitoring system comprises a field measurement device located in close proximity to the battery circuit, the field measurement device including an input mechanism for receiving current measurement data and an analog-to-digital converter for digitizing the received current measurement data. The battery monitoring system further comprises a monitor located remotely from the field measurement device, the monitor including a first communicator for receiving digitized data from the field measurement device.

Abstract: A battery control system for controlling the connection of a plurality of batteries to a load is provided. The system comprises a plurality of switches and a plurality of controllers. Each switch is operable to connect or disconnect one of the batteries from the load. Each controller is operatively coupled to one of the switches. Each controller is operative to cause one of the switches to disconnect one of the batteries from the load.

Abstract: A preload for use in a converter whose operating frequency changes with changes in load and/or input voltage. The preload is connected to the converter output to keep the operating frequency above the audible range of frequencies. The time for which the preload is connected to the converter output is inversely related to converter operating frequency. The preload is first connected when the operating frequency decreases to a predetermined frequency which is above the audible range of frequencies. As the operating frequency continues to decrease, the preload is connected for longer periods of time.

Abstract: A discrete-time, closed loop power factor corrector system controls the coupling of a delta-connected switched capacitor array to a 3- or 4-wire power line which may have time-varying, unbalanced, inductive loads. For inductive loads that cannot be exactly compensated with a delta-connected capacitance, the corrector system minimizes the total RMS reactive current drawn from the power line.