A dimmer is provided for controlling power to a load, the dimmer having a ground leakage power supply deriving power from a connection of the dimmer to ground. The power supply may be a switching-mode power supply that can be the sole or primary power supply to power operation of the dimmer, including operation of the controller.

A dimmer switch (110-x, 200, 400, 600, 700A, 700B, 1200) adapted to be coupled to an alternating current (AC) source and to a load so as to control an amount of power delivered from the AC source to the load, the dimmer switch may include: a triode for AC (TRIAC) (208, 408, 612) coupled between the AC source and the load, and which when triggered conducts to deliver a controlled amount of power from the AC source to the load for a corresponding half-cycle of one or more half cycles of the AC source. The dimmer switch may include first and second triggering circuits (606, 608) configured to trigger the TRIAC when charged after being enabled. One or more of the triggering circuits may be a self-balancing triggering circuit. The dimmer switch may further include a controller (412, 602, 1210) which selects and thereafter enables one or more of the first or second triggering circuits.

Power delivery systems and methods described herein conductively couple several input lines with a cable that conducts a multi-phase electric current. The input lines separately conduct different phases of the electric current. Output lines are conductively coupled with plural machines, and separately conduct the different phases of the electric current. Plural switching devices are conductively coupled with the input lines and with the output lines, and are used to control the switching devices in order to conduct the different phases of the electric current to the machines. A first set of the switching devices is closed to separately conduct the different phases of the electric current to a first machine of the machines. A different, second set of the switching devices is separately closed to separately conduct the different phases of the electric current to a different, second machine of the machines.

Techniques for an electronic device to perform power-stealing techniques to harvest energy from a power-control circuit to power components of the electronic device. In some examples, the electronic device may be connected in the power-control circuit between a power supply and a relay that is selectively configured to activate a power load. According to the techniques described herein, the electronic device may include voltage-drop circuitry that is connected in the power-control circuit such that a voltage drop is produced across electrical components of the electronic device while the relay is in the activated, or triggered, state. In this way, the electronic device may perform power-stealing from the power-control circuit while the relay is maintained in the activated state.

A phase gating controller includes a thyristor/triac having a control terminal and two power terminals, a sampling device for sampling a voltage present across the power terminals of the thyristor/triac and a control device configured to provide a control voltage at the control terminal in order to trigger the thyristor/triac. The control device is further configured to switch off the control voltage at the triggered thyristor and to detect an unexpected turning-off of the thyristor/triac if the sampled voltage exceeds a predetermined threshold value.

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 the load.

Power converters having bleeder circuits are disclosed. For example, in an embodiment, a power converter can include a controllable TRIAC in series with a rectifier that together produces a controllable rectified voltage at a first node, a first inductor having a first end and a second end, the first inductor being electrically connected to the first node at the first end, and electrically connected to a first power lead of a transistor and an anode of a diode at the second end, a load capacitor having a first end and a second end, the load capacitor being electrically coupled to the first node at the first end of the load capacitor, and electrically coupled to a cathode of the diode at the second end the load capacitor, control circuitry to control switching of the transistor, and a bleeder circuit coupled to the second end of the inductor, the bleeder circuit including a resistor in series with a coupling capacitor.

The present invention allows individual control of an output voltage of a main transformer and an output voltage of a teaser transformer while utilizing output characteristics of the respective transformer when a Scott connected transformer has control equipment arranged on the input side thereof, including first control equipment arranged in one of two phases of the main transformer on the input side in order to control a voltage or a current and second control equipment arranged in one end of a primary coil of the teaser transformer on the input side in order to control a voltage or a current, the control equipment controlling an output voltage of the main transformer and an output voltage of the teaser transformer individually.

The present invention allows individual control of an output voltage of a main transformer and an output voltage of a teaser transformer while utilizing output characteristics of the respective transformer when a Scott connected transformer has control equipment arranged on the input side thereof, including first control equipment arranged in one of two phases of the main transformer on the input side in order to control a voltage or a current and second control equipment arranged in one end of a primary coil of the teaser transformer on the input side in order to control a voltage or a current, the control equipment controlling an output voltage of the main transformer and an output voltage of the teaser transformer individually.

The present invention allows individual control of an output voltage of a main transformer and an output voltage of a teaser transformer while utilizing output characteristics of the respective transformer when a Scott connected transformer has control equipment arranged on the input side thereof, including first control equipment arranged in one of two phases of the main transformer on the input side in order to control a voltage or a current and second control equipment arranged in one end of a primary coil of the teaser transformer on the input side in order to control a voltage or a current, the control equipment controlling an output voltage of the main transformer and an output voltage of the teaser transformer individually.