Abstract: A current-balancing transformer is provided to supply plural parallel-connected electrical loads, especially loads such as gas discharge lamps which exhibit negative impedance and/or non-linear impedance over at least a part of their normal operating range. The current-balancing transformer forces current sharing among the loads so that each of the parallel-connected loads is supplied operating current.

Abstract: An inverter circuit having a pair of transistors connected to alternately and repetitively apply electrical energy to an inductive load. Short duration turn-off pulses are alternately applied to the transistors, and means are connected so that when each transistor is turned off, fly-back current induced in the load is applied to the other transistor to create a stored charge for turning it on and keeping it on until it receives its next turn-off pulse. Thus, no externally supplied repetitive forward base current is required.

Abstract: A push-pull inverter circuit for an inductive load such as a fluorescent lamp. A pair of transistors alternately and repetitively apply energy to the load, and are alternately rendered conductive by stored charges produced by flyback induced voltage in the load, in cooperation with a single mutual control circuit which repetitively renders the push-pull transistors nonconductive and removes their stored charges.

Abstract: An inverter circuit having transistor switches connected to alternately and repetitively apply a-c electrical energy to a load such as a fluorescent lamp. An oscillator control circuit supplies control pulses to the transistor switches in a manner to control their switching to insure a symmetrical waveform at the load. D-C power for the oscillator control circuit is obtained by rectification of the a-c load energy, and the oscillator frequency is adjustable by means of a control voltage.

Abstract: Particular combinations of two or more C.sub.12 -C.sub.22 fatty acid esters of C.sub.2 -C.sub.12 polyhydroxy compounds with C.sub.2 -C.sub.12 alcohol and a masking agent provide lubricants for aqueous well fluids having synergistic lubricity and cake conditioning properties in reducing torque and sticking in wells for natural resource fuel and/or mineral materials.

Abstract: An inverter circuit having two pairs of transistors, the transistors of each pair thereof being connected in series to alternately and repetitively apply electrical energy to an inductive load such as a fluorescent lamp. A square wave voltage is applied in opposite phase to electrodes of a first transistor of each pair thereof for rendering them alternately in condition for conduction and nonconduction. Each time a first transistor of one pair thereof becomes nonconductive, current in the inductive load reduces and an inductively induced flyback voltage is generated therein, which voltage is applied to the base electrode of the second transistor of the other pair thereof for creating a stored charge which turns on this transistor and keeps it on during the half-cycle, whereby the pairs of transistors are alternately turned on and off for applying alternating current through the load. Rapid discharge circuits are provided for the removal of residual stored charges.

Abstract: Lamp modulating circuitry particularly useful for flashing fluorescent lamps in response to music or other audio signals employs an input filter to screen out signals having frequencies less than 20 hertz or greater than 200 hertz. An amplitude demodulator detects the peak amplitude of signals received from the input filter and develops a signal representing the envelope of the low audio frequencies. An automatic gain control compares the instantaneous and average signals derived from the amplitude demodulator and develops an average signal using an output filter. Signals transmitted past the output filter are used by lamp flashing circuitry to cause the output of a fluorescent lamp to be modulated.

Abstract: A circuit for starting and ballasting a compact high intensity arc discharge lamp, and for preventing failure of the arc discharge. A filament connected in series with the arc lamp provides illumination during arc start-up and functions as a ballast during normal arc operation. An oscillatory starting circuit supplies starting voltage to the arc lamp until an operating arc is established. The circuit includes a "keep-alive" feature which prevents the arc from extinguishing during power fluctuations.

Abstract: A circuit for starting and ballasting a compact high-intensity arc discharge lamp. A filament connected in series with the arc lamp provides illumination during arc start-up and functions as a ballast during normal arc operation. An oscillatory starting circuit includes a transformer and a frequency-controlling ringing circuit, and applies starting voltage to the arc lamp until an operating arc is established. The circuit includes capacitor means for isolating the starting transformer from the operating path of the arc lamp, and further includes a voltage-doubling starting circuit and also a "keep-alive" feature which prevents the arc from extinguishing during power fluctuations.

Abstract: Gas burners, of the type employing atmospheric injection of combustion air and having a throat defining an inlet or mixing area and a plurality of burner ports defining an outlet area, particularly gas inspirators of the type having a plurality of peripheral orifices, so as to introduce pressurized gas into contact with atmospheric are. The inspirator is characterized both by the economic method of its construction, as well as its capability of adjustment to inspirate different types of fuels. In one embodiment, the inspirator conduit is axially adjustable with respect to the burner mixing throat, so as to regulate the injection of gas and mixing of gas with air prior to combustion. The inspirator in its multi-fuel mode has a plurality of series of axially spaced orifices, additional series being opened upon axial extension of the inspirator into the mixing throat.

Abstract: A circuit for shutting down an inverter that includes at least a series combination of first and second gate controlled rectifiers and a load. The circuit is comprised of means for sensing the direction and magnitude of the instantaneous current flowing through the load, and means responsive to the direction and magnitude of the sensed current for generating an output signal when the magnitude of the current exceeds a predetermined threshold level and the current is flowing in a first direction. The circuit further comprises means responsive to the simultaneous receiving of a shutdown signal and the generated output signal for further generating a gating pulse to be applied to the second gate controlled rectifier to cause the current flowing through the load to quickly extinguish. Further included is means responsive to the shutdown signal for inhibiting further regular gating of the gate controlled rectifiers to ensure quick turn off of the inverter.

Abstract: A circuit disposed between a power supply and a load for detecting the flow of an excess of power from the load back through the supply. The circuit is comprised of means for sensing the instantaneous current flowing between the power supply and the load, and means for sensing the instantaneous output voltage from the power supply. The circuit is further comprised of means responsive to the sensed instantaneous voltage and current for generating a signal that is indicative of instantaneous power flowing between the power supply and the load. Means is also provided for filtering out those components of the signal indicative of the instantaneous power which are at a frequency higher than the frequency of the AC current flowing between the power supply and the load to obtain a signal having a magnitude indicative of the average power flowing therebetween.

Abstract: A circuit for preventing overdischarge of a rechargeable lead acid storage battery. The circuit is comprised of means for sensing the rate of discharge of the battery, means for generating a safe final discharge voltage which varies inversely with the sensed rate of discharge of the battery, means for producing a triggering signal when the generated safe final discharge voltage is equal to or greater than the actual voltage of the battery, and means responsive to the trigger signal for disconnecting the battery from a load.

Abstract: A circuit for detecting a missed commutation in an inverter. The circuit includes means coupled to the center tap of a commutating interval current limiting reactor which is connected in series with and interposed between a pair of gate controlled rectifiers for generating a first signal upon detecting and for the duration of an interval when both of the rectifiers are ON. The circuit further provides means, responsive to a first pulse used to initiate an interval when either of the pair of rectifiers is to be "ON", for generating a second signal. Also provided is a means responsive to the first and second signals for generating a control signal to cause cessation of the operation of the inverter, if the first signal is absent during the total occurrence of the second signal.

Abstract: A variable frequency ac source drives a gas discharge lamp connected as a damping element in an otherwise high Q L-C circuit. Commutation of the ac source voltage is initiated as the instantaneous current drawn from the source equals a predetermined reference current level. Prior to lamp ignition the ac source drives the L-C circuit at resonance causing a voltage buildup which initiates an ignition. After ignition the source limits lamp current to provide a ballasting function.

Abstract: A circuit for detecting a malfunction in an inverter. The circuit includes means coupled to the center tap of a commutating interval current limiting reactor which is connected in series with and interposed between a pair of gate controlled rectifiers for generating a first signal upon detecting and for the duration of an interval when both of the rectifiers are ON. The circuit further provides means, responsive to a first pulse used to initiate an interval when either of the pair of rectifiers is to be "ON", for generating a second signal having a duration greater than the normal duration of the first signal. Also provided is a means responsive to the first and second signals for generating a control signal to cause cessation of the operation of the inverter, if the second signal is absent during the occurrence of the first signal.

Abstract: An electrical inverter circuit for converting d.c. electrical input into an a.c. electrical output involving the control of active switch elements in the primary of an output transformer circuit by, in part, providing a further controllable active element in circuit with the active element switches such that the primary winding current also flows therethrough. Synchronous control means are provided for synchronously controlling this further active element so as to increase its electrical impedance during at least a portion of each switching transition of the active element switch means so as to further aid and promote the rapid and efficient transitioning of the active element switches. Various alternative circuits are shown for this and for detecting the switch point as a function of primary transformer winding current and for further controlling the transition of the active switches in combination with the increased electrical impedance of the further controllable active element in circuit therewith.

Abstract: An electrical inverter circuit for converting d.c. electrical input into an a.c. electrical output involving the control of active switch elements in the primary of an output transformer circuit by, in part, providing a further controllable active element in circuit with the active element switches such that the primary winding current also flows therethrough. Synchronous control means are provided for synchronously controlling this further active element so as to increase its electrical impedance during at least a portion of each switching transition of the active element switch means so as to further aid and promote the rapid and efficient transitioning of the active element switches. Various alternative circuits are shown for this and for detecting the switch point as a function of primary transformer winding current and for further controlling the transition of the active switches in combination with the increased electrical impedance of the further controllable active element in circuit therewith.