Abstract: A low voltage AC power controller uses a line coupled capacitor AC to DC converter circuit to obtain energy from AC line power supplied to an AC load and may be used with an external high voltage AC switching device to control power supplied to the AC load. The line coupled capacitor AC to DC converter circuit provides a low power device that senses characteristics of the power supplied to the load and can communicate sensed information and/or receive control information related to the power supplied to load.

Abstract: A device for improving efficiency of an induction motor soft-starts the motor by applying a power to the motor that is substantially less than the rated power of the motor then gradually increasing the power while monitoring changes in current drawn by the motor, thereby detecting when maximum efficiency is found. Once maximum efficiency is found, the nominal motor current is found and operating ranges are set. Now, the phase angle between the voltage and the current to the motor is measured and power to the motor is increasing when the phase angle is less than a minimum phase angle (determined during soft-start) and power to the motor is decreased when the phase angle is greater than or equal to the minimum phase angle as long as the voltage does not fall below a minimum voltage determined during soft-start.

Abstract: The invention relates to a method for operating an electric motor (2) having a phase angle control with the following steps: Applying an AC voltage to a series connection of the electric motor (2) and a switching element (4), particularly a triac, wherein the switching element (4) connects through by applying an ignition signal and suppresses the flow of a current if the amount of current falls below a holding current; determining the time of a zero crossing of a virtual motor current that would flow if the switching element (4) were connected through; and turning on the switching element (4) at an activation time that is dependant on the time of the zero crossing of the virtual motor current.

Abstract: A power switch includes first and second MOS transistors in series between first and second nodes. Both the first and second transistors have a gate coupled to its substrate. First and second resistive elements are coupled between the gate of the first transistor and the first node, and between the gate of the second transistor and the second node, respectively. A triac is coupled between the first and second nodes. The gate of the triac is coupled to a third node common to the first and second transistors. A third MOS transistor has a first conduction electrode coupled to the gate of the first transistor and a second conduction electrode coupled to the gate of the second transistor.

Abstract: A circuit for controlling a triac, comprising: a bidirectional current-limiting active element connecting the triac gate to its opposite power electrode; and a switch connecting the gate to the other power electrode of the triac.

Abstract: A semiconductor based relay is provided for selectively coupling differing periodic power sources to loads through semiconductor switches provided therein while selectively using such power sources to also contribute to the operation of the relay circuitry, each in a different manner, in conjunction with selection signals.

Abstract: A semiconductor based relay is provided for selectively coupling differing periodic power sources to loads through semiconductor switches provided therein while selectively using the alternating polarity to constant polarity voltage converter outputs as switched in a separate circuit to also contribute to the operation of the relay circuitry in conjunction with selection signals.

Abstract: A power drawing circuit for a two-wire switching unit, the two-wire switching unit including a switching control circuit having its positive voltage input terminal connected in series to a load, the load being connected to one side of a power source.

Abstract: Circuit arrangement for controlling a triac.Triac control circuit with a mechanism (6) for sensing the gate voltage of a triac (2) and a gate pulse generator (11) responsive to the means for sensing. The gate voltage depends on the current through the triac and changes from a higher voltage value for a large triac current to a lower voltage value for a triac current closer to the triac holding current. By sensing the gate voltage it is possible to anticipate the triac turnoff and to generate a triac gate pulse before the triac turns off.

Abstract: Plug-in electrical switching devices which allow a load device to be electrically connected to and disconnected from an electrical power source at either: (a) a switched outlet electrically coupled between the power source and the load and (b) a location in the vicinity of the load.