Power Management Corporation

Other

John K Penrod

LeRoy J Carver

The following specification discloses an electrical power controller that has been specifically directed toward the control of lighting. The invention is directed toward reducing electrical energy consumption of high intensity discharge (HID) lamps and fluorescent lamps. The controller is connected at its input to a power line to light a bank of lamps or other electrical energy consuming devices. The output of the controller to the lamps can effectively be optimized at a substantially lower level, providing a high degree of lighting while effectuating a substantial energy saving. The output is controlled by a variable autotransformer having a drive motor that is in turn controlled by an amplifier comparator circuit. A bidirectional ramp generator provides increases and decreases of voltage in a manner to maintain the lights in their optimum operating condition. A timing circuit provides a timing function to allow for sufficient high voltage to light the HID lights over a prescribed period of time for the lights, after which it allows the system and controller to go to a low set point, which is sufficient to maintain the lamps in their lit condition. In the eventuality a load change occurs on the lighting bank, such as an increased series of lights being lit, a wattmeter output is fed back to a power change detector. This resets the controller for purposes of providing an increased amount of voltage sufficient to light the extra bank of lights while at the same time preventing the existing lights from being extinguished.

Electrical lighting controller

The power contactor for controlling the application of power to and the character of the current to a load includes a power relay having contacts connected between a source of power and the load, such as a motor or heater, with each of the contacts being provided with arc suppression means. A steering relay is provided to control the direction of current to a motor and thus its direction of rotation or the voltage applied to a heater. A control circuit insures that the steering relay contacts remain either open or closed while power is being applied to the load. The steering relay is provided with bracer bars to prevent short circuiting between relay contacts should any welding occur therebetween. The arc suppression means for each of the power relay contacts includes a solid state device, such as a triac, in parallel therewith, and auxiliary contacts for controlling the gating current to the triac. The auxiliary contacts close prior to either the opening or closing of the power relay contacts and open just after either the opening and closing of the power relay contacts, and therefore no gating current is applied to the triac while the power relay contacts are closed.

Power contactor and control circuit

A power contactor device includes at least one power relay contained within an electrically insulating plastic housing. Electrical busses carrying current to the relay contacts also serve as a means for removing the heat generated by those contacts and other electrical components within the housing. On the exterior of the housing, the busses have a large surface area and transfer heat through electrically insulating but thermal conducting material, such as alumina or beryllium filled epoxy, to a heat sink. The core of the relay is in metal-to-metal contact with the heat sink.

Cooling arrangement for electrical power contactor

An electrical contactor device includes a solid state arc suppression circuit connected in parallel with main relay contacts. Auxiliary contacts provide gating signals to the arc suppression circuit prior to, during and shortly after the main contacts open. Protection contacts connected in series with the arc suppression circuit are part of a relay which is actuated by additional auxiliary contacts of the main relay. The protection contacts prevent the arc suppression circuit from operating during initial closure of the main contacts thereby allowing the contactor device to be used in those applications where a high in-rush current is expected. A delay circuit holds the protection circuit relay contacts closed after the main relay contacts open to permit operation of the arc suppression circuit; the relay contacts thereafter open to isolate the arc suppression circuit and thereby to prevent any leakage current from flowing therethrough and to prevent any false triggering thereof. A fuse in the protection circuit prevents operation of the contactor device in the event the solid state devices become short circuited.

Contactor device including arc supression means

A method and apparatus for detecting an underfrequency condition of an alternating current power line is disclosed wherein the frequency of the power line is sensed, an underfrequency signal is developed whenever the power line frequency decreases below a predetermined frequency, a known frequency source is thereafter substituted for the alternating current power line, and the frequency of this source is checked by the same circuitry to produce a second output signal, and an underfrequency signal is generated in response to both first and second output signals.

Electronic underfrequency relay

An arc suppressor circuit for a relay includes a semiconductor means connected in parallel with the current carrying primary contact points. Auxiliary contact point means supply a gate signal to the semiconductor means to cause it to short the primary contact points during the closing or opening of the primary contact points. The circuit further provides for opening the auxiliary contact point means after the primary contact points are closed to prevent the semiconductor means from carrying load current for any substantial period of time. The semiconductor means may include a triac or a pair of silicon controlled rectifiers arranged to conduct on alternate half cycles.

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Bellbrook, OH, United States of America

John K Penrod