Magnetek, Inc.

George W Mortimer

Bryce L Hesterman

Robert Virgil Burke

Don V Folker

Dan Soule

A control circuit and ballasting means controls the light output of a gas discharge lamp in response to switches that are external to the ballast. The invention provides 3 levels of light output with single or multiple lamps. One embodiment of the invention can be mounted in a standard three-way socket for incandescent lamps. Another embodiment can be used to control multiple lamps in a ceiling-mounted fixture, replacing an inboard/outboard configured multiple ballast circuit. Other embodiments provide circuits that allow conventional dimming ballasts which are designed to be controlled with a low-voltage DC input signal to be controlled by a pair of switches connected to an AC power source.

Three-way fluorescent adapter

A universal input dimming circuit for coupling an isolated external control signal into a variable output power supply, particularly those used for driving fluorescent lamps. Circuitry is incorporated which allows to discriminate between a DC control voltage or a relatively low-frequency pulsewidth-modulated signal using the same pair of input leads. By appropriate conditioning and waveshaping, the circuit produces a pulsewidth-modulated output which is then coupled across an isolation boundary and then demodulated to provide a command signal to the dimming ballast.

Universal input dimmer interface

A two-winding, integrated-magnetic EMI filter provides damped common-mode and differential-mode inductances. The preferred embodiment of the filter has a magnetic core structure that incorporates a high-permeability C-core, a high-permeability I-core, and a low-permeability, lossy shunt. The three core pieces are assembled so as to form a structure that, similar to an E-I configuration, has two winding windows. The loss in the shunt aids in dissipating noise and it diminishes the effects of unwanted parasitic resonances by providing damping for the differential-mode inductance. Damping for the common-mode inductance is provided by losses in the C and I core pieces. Varying the reluctance of the shunt allows the differential-mode inductance to be adjusted separately from the common-mode inductance in order to tune the filter to remove desired noise frequencies. Another embodiment of the invention incorporates a high-permeability toroid core and a low-permeability, lossy shunt.

Integrated-magnetic filter having a lossy shunt

A fluorescent lamp power control having an input conditioning section, a lamp driver section, and a power command interface and control section to control power to fluorescent lamps. An external power command input is compared to an internally generated, computed power level and an electronic preregulator is controlled to regulate amp power. The preregulator output voltage and lamp driver current are multiplied to obtain a signal indicative of lamp power. A power command interface isolates the external power command input. Fluorescent lamp dimming is achieved by reducing the external power command input signal, reducing the power delivered to the fluorescent lamps.

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Fort Wayne, IN, United States of America

George W Mortimer