Litton Systems, Inc.

Magnetek, Inc.

Robert Virgil Burke

Thomas Eugene Hester

George W Mortimer

A lamp protection circuit for smaller gas discharge lamps and for compact fluorescent lamps powered by a ballast. The circuit protects against several lamp failure modes that can cause overheating and cracking of the lamp. Power levels in the lamp are sensed and when a level is exceeded, a control signal is generated. The circuit acts to reduce power in an electronic ballast powering the lamp and keeps the lamp powered down when either one of two fault conditions is sensed in the lamp. Several embodiments are disclosed.

Power sensing lamp protection circuit for ballasts driving gas discharge lamps

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.

Fluorescent lamp power control

An electronic ballast system for operating fluorescent lamps at full and partial brightness is disclosed having a series reactance selectively switched into or out of the system by a reactance switch. The electronic ballast has an input filtering section, a voltage-clamped current source, and an oscillator whose frequency is determined in part by load reactance. Series filament capacitors provide lamp filament power control during starting and running at full and partial brightness.

Fluorescent lamp dimming switch

A novel transistorized fluorescent lamp ballast and lamp combination operates from AC line voltage. The ballast provides for 'soft-start' lamp operation in one featured aspect and provides for some lamp light output regulation in another featured aspect thereof.

Solid-state ballast for rapid-start type fluorescent lamps

The specification presents an improved microwave oven power supply of the type which contains a transformer having a primary and high voltage secondary winding, a rectifier and capacitor combination connecting the high voltage secondary winding to a microwave magnetron and a control switching means, such as a Triac, is included in series circuit with the transformer primary to control current through the primary. In combination therewith a pulse generator is employed to control the operation of the switching means; providing voltage pulses to the switching means essentially to turn the switching means on and off for predetermined intervals. The improvement provides in the combination a pulse generator that contains a single control member accessible to the user, which varies or adjusts the width or duration of the pulses applied to the control switch means and concurrently varies or adjusts the time base or time period in which such pulses reoccur, suitably expanding the pulse duration concurrently with expansion of the time base, and vice versa. In an additional novel combination a synchronizer and an AND gate are connected in circuit with the pulse generator so that the concurrence of a synchronizing pulse from the synchronizer and a control pulse from the pulse generator must coincide in time before the Triac control switch means may be started.

Microwave oven power supply and oscillator therefor

A power supply for a microwave magnetron includes a transformer having a secondary winding, a capacitor connected to one end of the winding, a magnetron connected in between the remaining end of the capacitor and the winding so as to form a first unidirectional current conducting path capable of conducting current in one direction and a second circuit connected in shunt of the magnetron having unidirectional current conduction characteristics and being switchable to an On or Off condition, said second circuit being electrically poled opposite to the polarity of the magnetron and means for controlling the switching of the second circuit to its current conducting condition as a function of the magnitude of current through the magnetron.

Power controller for microwave magnetron

A microwave magnetron operating circuit includes a high leakage reactance transformer having a secondary winding a capacitor connected in series with the secondary winding and means connecting the series combination of capacitor and secondary winding across heater cathode and anode terminals of a magnetron. A controlled semi-conductor switch such as a triac is connected electrically in shunt of the magnetron. Control means are provided to operate the triac to its current conducting state so as to conduct current in shunt of the magnetron. The control means includes a positionable control member, accessible to the user, for varying the time at which the controlled semi-conductor device is placed in its electrically conductive state so as to permit the user to adjust or set the power supplied to the magnetron to various different power levels.

Growing community of inventors

Fort Wayne, IN, United States of America

Robert Virgil Burke