Abstract: A rectifier module assembly for a conventional three phase AC generator is formed into two crescent shaped rectifier modules so that the rectifier assembly can be mounted directly to the housing of the exciter rotor. The positive and negative rectifier modules are thermally conductive so that the exciter rotor itself can act as a heat sink for the rectifier module assembly. The rectifier module assembly occupies the space between and around the generator shaft and the exciter rotor windings.

Abstract: A transformer enclosure design with a separate receptacle housing used for power transformers especially those used with neon lamps. The separate receptacle housing allows for multiple neon gas discharge tube mounting orientations and allows for multiple transformer mounting configurations with one enclosure design. The receptacle is used to connect the ends of a gas discharge lamp to the transformer. The receptacle housing contains a pair of recessed bushings and features a removable mounting bracket that can be mounted in several positions. Connection between the receptacle housing and the transformer housing is through flexible GTO wiring. The design allows an almost infinite number of spatial mounting orientations so that any tube orientation may be accommodated.

Abstract: 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.

Abstract: In accordance with the present invention, a hybrid sequence start circuit is provided for operating a plurality of instant start lamps. The circuit utilizes two coils, a primary and a secondary, and an electronic switch to start a plurality of series-connected, instant start lamps in sequence. When the circuit is energized, the electronic switch causes open circuit voltage to be applied to a first lamp by placing a low impedance across the other lamps, causing the first lamp to strike. The first lamp then conducts current, causing a starting capacitor in parallel with a second lamp to be charged, eventually, causing the second lamp to strike. The current through the second lamp shunts current away from the switch, and when this current drops below a predefined threshold level, the switch opens, effectively removing both the low impedance and the starting capacitor from the circuit.

Abstract: In a power inverter, ripple current and bulk filtering are provided by a high-current, high-microfarad film capacitor arrangement; there is no separate snubber capacitor section. In an alternative embodiment, a small high-frequency film capacitor is connected in parallel with the bulk film capacitor arrangement, thereby increasing the operating range of the circuit.

Abstract: An improved connection assembly for connecting a centrifugal governor to the shaft of a fractional horsepower electric motor. The end of the rotor shaft to which the governor is mounted is provided with a circumferential ring seat and is flattened on diametrically opposed sides at the tip of the shaft. The governor assembly carrier plate is provided with a mounting sleeve that is shaped to mate with the flattened sides at the end of the rotor shaft. The mounting sleeve also has an opening that mates with the circumferential ring seat so that when the carrier plate is placed over the end of the rotor shaft, the carrier plate and the rotor shaft can be rotated 90 degrees relative to each other and the carrier plate will be captured by the ring seat to hold the governor assembly in place. A bowed retaining ring is also fitted within the ring seat and between the governor and the stator of the motor forcing the carrier plate of the governor assembly toward the end of the shaft.

Abstract: The present invention provides a sensorless circuit for detecting rotational speed of a rotor in an induction motor. The circuit includes a switch between the AC source driving the motor and a motor phase winding. When the switch is closed, there is developed across the phase winding a voltage waveform from the AC source. When the switch is subsequently opened, there is developed across the winding a residual voltage waveform induced by the rotor. The speed of the motor is determined by measuring a time interval between selected points on the voltage waveform.

Abstract: An electronic ballast includes a low cost circuit for power factor correction. A PWM circuit utilizes a wave form signal derived from the ballast inverter as a reference. The reference wave form signal is combined with a feed back signal to form a composite control signal that is compared with the reference voltage to create a pulse width modulated signal.

Abstract: A protection circuit for non-isolated ballasts that drive gas discharge lamps to prevent shock hazards. The device acts to prevent excessive leakage currents from flowing between the ballast and ground by introducing a higher common mode impedance path in the circuit. A two stage common mode filter assembly has a first common mode inductor series connected to a second common mode inductor. A first capacitor is connected across the common mode inductors. A second capacitor is connected between the junction of the first capacitor, the first inductor, the second inductor and ground. The circuit protects by reducing high frequency leakage currents.

Abstract: An electronic ballast has a protection circuit particularly useful for smaller diameter gas discharge lamps including compact fluorescent lamps. The protection circuit prevents lamps from overheating by preventing the ballast from providing sustained output power when the magnitude of the ballast output voltage indicates abnormal lamp operation. The protection circuit has a voltage sensor which develops a voltage that is more negative than the negative DC supply terminal of the inverter so that an inexpensive low-voltage SCR can be used to turn off the inverter. The circuit provides automatic restarting of the ballast after a new lamp has been installed to eliminate the need for toggling the input power to the ballast.

Abstract: A method of assembling a leadless type ballast transformer having a connector at one end of the housing for accepting a mating connector which supplies voltage to the ballast and provides the operating voltage to the lamps controlled by the ballast. Uninsulated connection leads extending inwardly of the housing from the connector terminals to contact the lugs of a terminal board adjacent a transformer coil with the magnet wires of the transformer coils also being in contact with the terminal board lugs. The connection leads and magnet wires are permanently electrically connected to the terminal board lugs by ultrasonic welding.

Abstract: A preferred embodiment of the present invention provides a ballast circuit, comprising three sections: an input power section that receives a line AC signal as an input and provides a DC signal as an output; a pre-regulator section that conditions the DC signal; and a lamp driver section that drives a gas discharge lamp load. The pre-regulator section includes a transformer with an input winding, an output winding, and a current sense winding. The input winding receives the DC signal provided by the input power section. The output winding is connected in a flyback configuration with a flyback blocking diode, a bulk storage capacitor, and an output terminal for the conditioned DC signal. The current sense winding generates a signal proportional to the level of the transformer current. The transformer current is controlled by a flyback switch. A resonant capacitor is connected between the flyback switch input and ground, the resonant capacitor and the transformer forming a resonant circuit.

Abstract: The present invention provides a method and circuit for controlling the flow of current through a load. In a preferred embodiment, an oscillator generates a pulse signal of constant frequency. A pulse width modulator adjusts the duty cycle of the pulse signal in response to a dimming level signal input indicative of the desired level of current flow through the load. A converter receives the pulse signal as an input and converts it into an AC signal, the frequency of which follows the frequency of the pulse signal and the symmetry of which varies with the duty cycle of the pulse signal. The load is connected into a resonant circuit tuned such that a change in the symmetry of the AC signal changes the level of current flowing through the load.

Abstract: The present invention provides a low-cost power factor corrected electronic ballast circuit. A preferred embodiment includes a discontinuous conduction mode boost power factor correction circuit that is controlled with a simple pulse-width modulator (PWM) circuit comprising a few discrete components instead of an integrated circuit. The PWM circuit utilizes a reference waveform signal derived from the ballast inverter. The reference waveform is combined with a feedback signal to create a composite signal that is compared with a reference voltage to create a pulse-width-modulated signal. The feedback signal is used to regulate the bulk DC voltage. In an alternative embodiment, a feedforward signal that is proportional to the time-varying level of the rectified line voltage is added to the reference waveform and the feedback signal, and serves to modulate the pulse width of the boost circuit in a manner that reduces the harmonic distortion of the input current.

Abstract: A magnetostrictive liquid level probe in a double-walled liquid container develops liquid level data and external sensors in the space between the walls respond to the presence of liquid leaked into the space from inside or outside the container. Other sensors external of the liquid level probe may sense other conditions. The probe electronics determines binary states of the external sensors and digitally encodes the states for inclusion in data transmission of the liquid level information to a remote controller via a two-wire transmission line. One embodiment develops pulses spaced as a digital function of the sensor states and includes liquid level data between the pulses for transmission. The pulse space is measured at the remote controller and decoded to determine the external sensor states, while the liquid level data is analyzed to determine the contents of the container.

Abstract: A laminar board for printed circuits is described, consisting of a base layer (1) made of a material with a high coefficient of thermal conduction and, on at least one side (1B) of the base layer, a coating (13) of electrically insulating material forming the surface for the application of the conducting tracks (11) of the printed circuit. The base layer (1) has at least one deformed area with a depression (3A) on one side (1A) and a corresponding projection (3B) on the opposite side (1B), the insulating coating (13) being applied to the side (1B) on which the projection (3B) is disposed, forming a surface substantially free of discontinuities, with a lesser thickness at the position of the projection (3B) and a greater thickness in the areas adjacent to the projection; the power components (15) of the circuit are fitted over the projection (3B).

Abstract: A leadless type ballast transformer having a connector at one end of the housing for accepting a mating connector which supplies voltage to the ballast and provides the operating voltage to the lamps controlled by the ballast. Uninsulated connection leads extending inwardly of the housing from the connector terminals to contact the lugs of a terminal board adjacent a transformer coil with the magnet wires of the transformer coils also being in contact with the terminal board lugs. The connection leads and magnet wires are permanently electrically connected to the terminal board lugs by ultrasonic welding.

Abstract: A constant wattage ballast transformer of the isolated type permitting the electrical grounding of a mounting shell of the lamp it powers in which a primary, secondary and auxiliary winding are provided with the primary winding inducing voltage into the auxiliary and secondary windings while being electrically isolated from both these windings and the auxiliary winding electrically connected to the secondary winding to add its induced voltage to that directly induced in the secondary winding from the primary winding.

Abstract: One half-connector terminates a set of leads in the ballast, for carrying electrical power to and from the ballast coils. Another half-connector terminates another set of leads outside the ballast, connected e.g. to carry power to lamp sockets. Male contacts, preferably formed very inexpensively as bared ends of one set of leads, are held in a first of the half-connectors; female contacts, connected to the other set of leads, are held in a second of the two half-connectors. Through-holes in the second half-connector each hold one female contact; each hole has a necked-down section, forward from the contact, and some device (preferably an ultrasonically displaced slug) to retain the contact. In one aspect of the invention, each hole also has a bore whose transverse preformed dimension is biggest immediately rearward from the necked-down forward section.

Abstract: The electronic reactor for discharge lamps (L) comprises a bridge rectifier (5) connected to an alternating voltage source (3); a half-bridge with two controlled switching means (11, 13) made alternately conducting to connect the said lamp (L) and the said bridge rectifier (5); a resonant load circuit (17) connected to the said half-bridge (11, 13); and a smoothing capacitor (29) connected in parallel with the half-bridge (11, 13). An auxiliary resonant circuit (33) is provided to reduce the crest factor and correct the power factor between the output (19) of the half-bridge (11, 13) and the positive pole (5A) of the bridge rectifier (5).