Abstract: An active interphase reactor for twelve-pulse diode rectifiers is disclosed. The system draws near sinusoidal currents from a power utility. In one embodiment, a low kVA (0.02 P.sub.o (PU)) active current source injects a triangular current into an interphase reactor of a twelve-pulse diode rectifier. This modification results in near sinusoidal utility input currents with less than 1% THD. In alternative embodiments, a low kVA, 12-pulse system with an autotransformer arrangement (kVA rating of 0.18 P.sub.o (PU)) is implemented with the proposed active interface reactor. The resulting systems draw clean power from the utility and are suitable for powering larger kVA ac motor drive systems.

Abstract: An electronic delay turn off switch including a bridgelike array of four diodes disposed between an alternating current power source and a load wherein the diodes have anodes and cathodes in opposing disposition and having an SCR with anode connected to the interconnected cathodes and with cathode connected to the interconnected anodes. A gate isolation diode, a switch, a resistor-capacitor charge mode timer, and a DIAC are interconnected between the SCR anode and gate thereby providing an SCR turn on whenever the switch contacts are closed, and a delayed SCR turn off whenever the switch contacts are opened. In an alternate embodiment a variable resistor is added to enable user selection of the duration of turn off delay.