Abstract: A system and method for eradicating burrowing rodents uses an internal combustion engine running at high speed and zero mechanical load to convert gasoline and air into pressurized carbon monoxide entrained in an inert gas mixture consisting mostly of nitrogen and water vapor. A heat exchanger cools the exhaust gas and provides it to one or more outputs. Respective hoses are coupled to the outputs, with each hose coupled to an injector tube adapted for insertion into a subterranean tunnel in which a rodent may be present. The engine is preferably mounted on a wheeled tubular frame which may be part of a hand truck or a trailer frame, with the frame serving as both structural member and as heat exchanger. The system pumps gas into the tunnel, replacing the existing atmosphere with oxygen poor, CO rich gas that causes the rodents to succumb to a combination of CO poisoning and hypoxia.

Abstract: A battery charging method and system with a temperature-compensated charge profile requires that, during a ‘bulk stage’, a regulated constant charge current is provided to the battery until the voltage across it increases to a predetermined ‘absorption stage voltage limit’, at which time charging transitions to an ‘absorption stage’. During the absorption stage, a charge current is provided which maintains the voltage across the battery at the absorption stage voltage limit, until: 1) the charge current falls to a predetermined current threshold, 2) the charge delivered to the battery during the absorption stage reaches a predetermined charge threshold, or 3) the difference in charge between two successive intervals of equal duration becomes zero, at which time charging transitions to a ‘float stage’. During the ‘float stage’, a regulated constant charge current is provided, such that the voltage across the battery varies with the temperature of the battery.

Abstract: An engine cranking motor soft-start system and method includes at least one cranking motor and a switching power converter which is coupled to the cranking motors such that the voltage across the motors varies with the converter's duty cycle. The duty cycle, and thereby the voltage across the motors, is gradually increased over a predetermined period. This serves to limit the acceleration of the cranking motors, and thereby their peak current and torque, which may serve to increase their service life. The cranking motors are typically operatively coupled to drive respective pinion gears which are brought into engagement with a ring gear when starting the engine. The system is preferably arranged such that the gradually increasing duty cycle results in the torque of the cranking motors being sufficient to break an abutment that may be present between the pinion gears and the ring gear.

Abstract: A battery charging method and system with a temperature-compensated charge profile requires that, during a ‘bulk stage’, a regulated constant charge current is provided to the battery until the voltage across it increases to a predetermined ‘absorption stage voltage limit’, at which time charging transitions to an ‘absorption stage’. During the absorption stage, a charge current is provided which maintains the voltage across the battery at the absorption stage voltage limit, until: 1) the charge current falls to a predetermined current threshold, 2) the charge delivered to the battery during the absorption stage reaches a predetermined charge threshold, or 3) the difference in charge between two successive intervals of equal duration becomes zero, at which time charging transitions to a ‘float stage’. During the ‘float stage’, a regulated constant charge current is provided, such that the voltage across the battery varies with the temperature of the battery.

Abstract: A stabilized control system and method for smoothly connecting and disconnecting an induction generator to the utility power grid is described. Thyristor switches are interposed between each phase of the mains and the generator. The thyristors are gated so as to decouple the generator from the mains for a period during each mains half-cycle, the decoupling period decreasing as the generator power factor angle increases as the generator is driven by the prime mover to its synchronous speed and above. A feedback circuit processes the generator terminal voltage to produce an analog feedback signal level proportional to the thyristor blocking voltage. The feedback signal is used to increase the thyristor gate delay angle as the generator voltage increases with increasing generator output power. This causes the rate-of-change of the generator voltage with respect to generator speed to be less than it would be with no feedback signal present.

Abstract: A self-controlled polyphase synchronous motor drive system having means for producing rotor digital timing signals representative of the position of the rotor relative to the stator, means for producing pulse width modulation control signals wherein the pulse width thereof is responsive to a motor power factor command signal, a plurality of phase control means equal in number to the number of phases of the polyphase stator and responsive to the variable pulse width modulation control signals and including means for producing a modulated analog reference signal from one of two selected stator voltages and means for summing the amplitude modulated analog reference signal with an unmodulated analog reference signal produced from the other of the two selected stator voltages and for comparing the sum thereof with a threshold voltage signal to produce as an output therefrom two motor voltage derived digital timing signals for each phase of the polyphase stator in response to the speed of the motor such that an abs

Abstract: A voltage control system for an induction motor, consisting of a SCR AC voltage controller with sensing and control circuitry, adjusts the motor voltage in response to the load torque demand, thereby minimizing the motor's magnetizing current and its associated losses. The motor displacement power factor angle, which is responsive to load torque, is sensed by directly sensing the motor voltage, deriving its fundamental or line frequency component, and phase-comparing that component with a similiarly derived fundamental component of the motor current. The resulting displacement power factor signal is amplified, together with a stability augmentation signal, to form a phase delay command signal for the AC controller. The stability augmentation signal, representative of the blocking voltage across the AC controller SCRs, is formed by rectifying the 180 Hz single phase sum of the three motor voltage signals.

Abstract: A rotatable transformer field excitation system for an armature converter-fed variable speed self-controlled brushless polyphase synchronous motor wherein the armature converter is energized from an alternating current voltage source having one or more phases, and wherein the motor includes a rotor having a wound field winding and a rectifier circuit mounted on the rotor and rotatable therewith to energize the field winding with direct current from the rectifier circuit, and wherein the rotatable transformer includes a primary winding having a number of phases equal to the phases of the alternating current voltage source and having a plurality of coils located in slots on the inner periphery of and defining at least two poles of a rotatable transformer stator, the slots being spaced a predetermined distance from the center of the rotor axis, and a separate rotatable secondary winding, the number of phases of which equals the phases of the rotatable transformer, the secondary winding being formed by a pluralit

Abstract: A heat sink assembly is described for cooling right cylindrical packages containing high power semiconductor devices. Opposite end faces of the packages cooperate with heat sink members to provide liquid coolant flow channels in which the liquid coolant is in direct contact with the package end face. A unique compact elastomeric coolant manifold facilitates semiconductor device replacement in the assembly. The assembly, including the elastomeric manifold, is enclosed in a container and maintained submerged in coolant during use.

Abstract: In a cycloconverter system, a circuit for maintaining the gate drive signal on the gate of each controlled rectifier when the gate drive command for the controlled rectifier terminates prior to the time when the controlled rectifier would normally become conductive. Voltages across the controlled rectifier are monitored by voltage sensors. Logic circuits are provided which are responsive to the outputs of the voltage sensors and the presence of gate drive commands for maintaining a gate drive signal on the gate of a controlled rectifier when the gate drive command for the controlled rectifier terminates after the controlled rectifier reverse blocks and until it becomes conductive.