Abstract: There is disclosed a phase-controlled switching circuit, comprising a controlled rectifier (e.g. bidirectional triode thyristor); an amplifier connected at its output terminal to the gate of the controlled rectifier; an ac Wheatstone bridge having at one of its arms a variable resistance (e.g. thermistor to CdS photoconductive cell), said ac Wheatstone bridge being connected at one branch to the input terminal of the amplifier and at its other branch between the cathode and anode of the controlled rectifier through a load; a time constant circuit connected with the variable resistance; a pair of mechanical contacts (e.g. relay) connected in parallel with the controlled rectifier and a dc source for electrifying the whole circuit.

Abstract: An inverter comprises a pair of reactors connected in series between a positive arm element and a negative arm element, snubbers each connected in parallel to respective arm elements, and a feedback circuit for transferring electrical energy stored in the snubbers back to the d.c. power source. The feedback circuit includes a self turn-off switching device which is controlled to become conductive during a certain period in correspondence to the on-off operation of the arm elements so that energy stored in the snubbers is fed back to the d.c. power source through a current transformer and a rectifying circuit during the on-state of the device.

Abstract: A microprocessor controlled battery charger utilizes a high frequency switching circuit and a means to read the voltage of the battery plus a timer in the circuit wherein the microprocessor is connected both to the timer and to the voltage reading means and establishes a decreasing step charging rate of the battery so as to charge the battery at a first charging rate, then at a second lower charging rate until the rate of change of voltage with time is less than a small amount of volts per hour and then the current is reduced to a third charging rate for a finishing charge of the battery. In the preferred embodiment the first charging rate is maintained until a predetermined battery voltage is achieved and the third charging rate is maintained for a given period of time.

Abstract: An improved arrangement for powering a two-way portable radio or the like comprises rechargable battery cells and sets of power input and output contacts interconnected to each other and the battery cells in such a way that the output contacts may be electrically connected to the battery cells for powering the radio, or to the input contacts for receiving power directly from a battery charger for dead battery operation while simultaneously recharging the battery cells, all battery pack contacts being electrically isolated from the battery cells in the latter mode of operation.

Abstract: In an exemplary embodiment, a battery conditioning system monitors battery conditioning and includes a memory for storing data based thereon; for example, data may be stored representative of available battery capacity as measured during a deep discharge cycle. With a microprocessor monitoring battery operation of a portable unit, a measure of remaining battery capacity can be calculated and displayed. Where the microprocessor is permanently secured to the battery so as to receive operating power therefrom during storage and handling, the performance of a given battery in actual use can be accurately judged since the battery system can itself maintain a count of accumulated hours of use and other relevant parameters. Where an embodiment includes a main battery and a backup battery, the voltage of each may be individually measured, and each may be conditioned. Battery capacity of each may be measured.

Abstract: The invention is directed to an electronic switching power supply for the controlled charging of a storage battery (61) with a boost- or trickle-charge current in dependence upon the charge condition of the battery, including a primary-pulsed blocking oscillator type converter in which the primary coil (51) of a transformer (5) is connected in series with a switching transistor (1) while its secondary coil (52) is connected in series with the storage battery (61) and a diode (31). Provided in parallel with the series connection comprising the storage battery (61) and the diode (31) are a capacitor (12) and a further diode (32) connected in series, with a switching arrangement (71) provided in parallel with the capacitor (12) being connected via a decoupling arrangement to the base of a second transistor (2) determining the turn-on period of the first transistor (1).

Abstract: A power supply circuit for producing at least one output which is essentially free from current ripple is disclosed. A chopped DC voltage source is applied to a transformer having a primary coil and at least two secondary coils. The secondary coils provide input voltages to output stages which each include a rectifier diode, a freewheeling diode and an LC filter. The inductors in the LC filter of adjacent output stages are magnetically coupled together. The characteristics of these inductors are selected such that the current ripple through the inductors in all the output stages, other than the first output stage, is essentially zero. Multiple inductors can also be employed in the first output stage with each one being magnetically coupled to the inductor in a different succeeding output stage.These multiple inductors in the first output stage can be combined in series or in parallel.

Abstract: Transfer apparatus for use with an AC generator having a field winding, the DC energization of which controls the output of the generator. Associated with the generator are first and second voltage regulators each including means for sensing the output of the generator and means for varying the DC energization of the generator field winding to regulate the output of the generator to a respective reference level for each voltage regulator. The transfer apparatus includes a circuit for generating a first signal as a function of the generator output as sensed by the first voltage regulator sensing means and a second signal as a function of the generator output as sensed by the second voltage regulator sensing means. Another circuit independently produces an additional signal to which the first and second signals ordinarily have a predetermined relationship. A further circuit selects the first or second voltage regulator to energize the generator field winding.

Abstract: The invention concerns a converter (2) provided with GTO thyristors the frequency and characteristic shape of its output voltage (U.sub.A) being constrained by a load (3). The frequency of the converter (2) is matched to the constrained output voltage (U.sub.A) with the aid of a regulating circuit (4). Non-simultaneously switched GTO thyristors are switched on and off in a predetermined timed relation to each other (FIG. 3).

Abstract: A charger for a battery-operated surgical machine includes a charging circuit and a housing. The housing contains the charging circuit and is provided with at least one plug receptacle means for the battery component of the surgical machine. The housing is also fitted with a selector switch connected to the charging circuit. In a first position of the selector switch the charging circuit charges the battery immediately, while in a second position of the switch the charging circuit first discharges the battery down to a predetermined lower potential and then charges it up to a predetermined higher potential.

Abstract: A battery charging circuit includes a silicon controlled rectifier full wave bridge that has its input connected across a conventional 60 hertz alternating current power line. The output of the bridge provides 120 hertz pulsating direct current to the battery being charged. The duration of each direct current charging pulse is determined by phase triggering of the silicon controlled rectifiers in the bridge. The silicon controlled rectifiers are triggered at a predetermined, identical firing angles by a conventional unijunction transistor relaxation oscillator which in turn is regulated by an output voltage and output current sensing circuit that established the noted firing angles so as to regulate, and limit at desirable upper valves, the charging voltage and current applied to the battery.

Abstract: A resonant converter feeds five load circuits while maintaining excellent voltage regulation. The power converter features a non-bifilar wound transformer with the resonant capacitors serving the dual function of suppressing diode voltage switching transients while forming the resonant circuit in conjunction with the transformer. Overcurrent circuit protection is also provided.

Abstract: An electromagnetically operated relay having a spring which compensates for misalignment of a moveable block as shown and described. The movable block reciprocates within said relay housing in response to forces exerted by the electromagnet. The block includes projections which engage openings in an leaf spring which biases the block. The spring to block engagement provides compensation for misalignment of the block, and for unequal forces applied to the block and/or spring.The compensation provided by the spring to block engagement is achieved by a loose fit between projections on the slidable block and openings in the spring. The freedom of movement provided by the slots allows the spring to bulge in a direction opposite to the force on the spring end with respect to the sliding block. By creation of this bulge between the two two projections on the sliding block, compensation is provided to the spring system.

Abstract: An electronic battery charger for charging various types of dry cells including nickel-cadmium batteries provides for a cool down phase during battery charging cycle once a maximum predetermined temperature or voltage for the battery has been sensed. Subsequent to the cool down phase, a charging current is controlled in a manner such that, as battery temperature continues to decrease, a control device increases the charging current applied to the battery. Once a reheating of the battery is detected, the control device decreases the charging current. In this manner, a maximum charge is achieved in the battery at a temperature close to the ambient temperature.

Abstract: A method and apparatus are disclosed for use with a battery powered inverter for powering a load through a ferroresonant transformer. The current flow through the inverter-ferroresorant transformer is sensed and is utilized to modulate the inverter's pulse width at a point, after a peak voltage but before saturation begins, when the slope of the inverter-ferroresonant transformer current with respect to time is at or near zero. A maximum current limiting feature can be provided in the method and apparatus of the present invention.

Abstract: A secondary battery operating method for charging and discharging a secondary battery using zinc as the negative electrode active material. After the termination of the normal discharge, direct current supply means is connected to the secondary battery in opposite polarity relation with each other and the secondary battery is reverse charged in a polarity opposite to the normal polarity. As a result of this reversed charge, the zinc remaining on the negative electrode after the termination of the normal discharge is completely dissolved into the electrolyte. If necessary, the energy stored in the secondary battery after the termination of the normal discharge is regenerated during the reversed charge.

Abstract: A process and apparatus for controlling the charging of pressurized gas-metal cells such as nickel-hydrogen cells, to prevent detrimental overcharging, wherein the time rate of change of a battery gas pressure index is monitored as a control parameter. When the time rate of change of the index falls below a preselected value, charging is discontinued. The cell gas pressure index can be gas pressure itself, or a quantity which is responsive to, and depends upon gas pressure, such as the deformation of a cell component.

Abstract: A dual voltage motor vehicle electrical system wherein a pair of batteries are connected in series across the direct voltage output terminals of a bridge rectifier that is connected to the output winding of an alternating current generator. First and second groups of controlled rectifiers are connected between a junction of the batteries and the generator output winding. In low speed operation of the generator the groups of controlled rectifiers are alternately biased conductive. The time period of conduction of the groups of controlled rectifiers is controlled as a function of the difference in the voltages across the respective batteries. At a higher speed of the generator one of the two groups of controlled rectifiers is biased conductive, dependent upon the relative magnitudes of the voltages across the batteries.

Abstract: A grounded capacitor in a switched-mode power supply provides AC line EMI filtering, reduced current leakage, and high voltage isolation. The capacitor is coupled between an AC rectifier circuit and the controlled switching devices of the power supply to provide the capacitor with a lower conduction angle, i.e., the grounded capacitor will only conduct a leakage current during periods when diodes within the rectifier circuit are conducting. The low impedance ground return path for the switching device output signal permits the use of a filter capacitor having a large capacitance which affords improved power supply line isolation and enhanced safety.

Abstract: An apparatus for charging electric storage batteries comprises a host computer for providing charging information to and receiving status information from a plurality of slave computers. The slave computers are coupled to the host computer by means of a fiber optic data link. A plurality of control modules are coupled to each slave computer. Each control module applies charging current to a plurality of electric storage batteries in response to instructions received from the slave computer. Each control module also sends charging and battery temperature status information back to its respective slave computer.