Abstract: A redundant power system includes plural load-sharing power supplies connected to a common AC output bus. Identical circuitry is provided in each supply to control the redundant operation and is connected to each of the others via a common redundancy bus. An arbitration circuit in each supply selects a master power supply based on which supply detects the lack of a master supply first via the redundancy bus. A synchronization circuit in each slave supply synchronizes the polarity of the respective AC output with that of the master supply via the redundancy bus. A redundant bias circuit in each supply provides operating power to the redundancy circuitry in the respective supply from a common bulk voltage provided on the redundancy bus. A soft-start circuit in each supply allows all the supplies to start producing power at the AC output bus in unison. An overvoltage correction circuit in each supply detects an overvoltage on the AC output bus and shuts down only the supply which is causing the overvoltage.

Abstract: An uninterruptible power supply includes an inverter provided with power from a utility and a battery. The battery is connected through a FET so that battery power is instantly supplied to the inverter through the intrinsic FET diode when the utility power fails. The battery discharge FET is operated by an oscillator driven control circuit. The inverter includes an amplitude circuit and a polarity circuit. The inverter amplitude circuit includes FET operated by driver circuits that ensure efficient switching. The phase shifted full bridge pulse width modulated amplitude circuit converts the input power to a pulse width modulated output representing the amplitude of the power supply voltage, which is switched by the polarity circuit and to obtain the desired output voltage polarity. A falling edge bleeder ensures that a decreasing output voltage magnitude follows the desired waveform.

Abstract: A linear voltage regulator is operated by a temperature sensor and a current sensor. The temperature sensor is a thermistor in a voltage divider connected across the output of the regulator. The current sensor operates a voltage follower connected to adjust the voltage in the voltage divider. The regulator controls voltage supplied to a cooling fan in a power supply. The sensed temperature is the air temperature near the power supply enclosure. The sensed current is the output current of the power supply. When the ambient temperature increases and/or the power supply output current increases, the voltage regulator increases the fan speed by raising the voltage. The current sensor can also be used to sense other parameters, such as voltage.

Abstract: A combined terminal block mount and lamination stack keeper has a metal keeper with a flat first portion of a size and shape to lie contiguous to and oriented with a stack of laminations. A part of the stack of laminations is adapted to receive an inductance coil, and the coil is adjacent a part of the keeper first portion. There is a bend in the keeper to establish a unitary mounting strip out of the plane of the keeper first portion, and the mounting strip has a width and thickness to mount a terminal block thereon. The foregoing Abstract is merely a resume of general applications, it is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A finger-safe terminal block has an insulator base with two separate rotatable screws in screw apertures leading to first and second clamp areas. First and second conductor apertures also lead to these clamp areas. A tool access end accessible from the exterior of the base is provided on each screw so that tightening of each screw is adapted to physically clamp an end of an external conductor in the respective clamp area. The screw apertures and the conductor apertures at the exterior surface of the base are smaller than an adult human's fingertip so that such fingertip cannot touch any electrically energizable conductor in the terminal block. The foregoing Abstract is merely a resume of general applications, it is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A voltage regulator for a sealed rechargeable storage battery containing one or more rechargeable working cells and at least one regulator cell. The regulator cells are capable of consuming gas in a gas space within the sealed battery during charging of the working cells. The regulator cell is in gaseous communication with the gas space, and having a voltage stabilizer maintaining a preselected voltage range to the regulator cell and maintain a current to the regulator cell depending on the gas to be consumed.

Abstract: A low loss clamp circuit is provided for a dc to dc converter. The converter has a transformer with a secondary winding and a secondary circuit and a center tap primary winding. A dc voltage input is supplied to the primary winding center tap and to a circuit ground. A rectifier such as a bridge rectifier connects to two ends of the secondary winding and to the circuit ground to supply a dc output voltage. A pair of semiconductor switches such as FET switches are provided. Each end of the primary winding is connected through a respective switch to the common ground. The various circuits have energy storage means including the input capacitor 31 and input choke 32 in circuit with the primary winding. It will also be noted that the output capacitor 29 is a part of the energy storage means. This energy storage means is connected to return energy to the secondary circuit, not the primary circuit.

Abstract: A sealed rechargeable storage battery containing one or more rechargeable working cells and at least one regulator cell. The working cells are capable of generating gas in a gas space within the sealed battery during charging of the working cells. The regulator cell is in gaseous communication with the gas space, the regulator cell being chargeable and dischargeable by a control circuit to regulate the amount of gas in the gas space.

Abstract: A terminal structure and seal for an electrochemical cell includes a terminal post inside a plastic tubular member which is inside a metal barrel. The plastic tubular member is unitary with the plastic cover and a reinforcing boss on the cover is annular and an annular stabilizing flange unitary with the metal barrel is embedded in this reinforcing boss. The metal barrel is separated from the interior of the electrochemical cell so that the metal barrel need not be resistant to the electrolyte and so that there is no potential leakage path between internal threads on the metal barrel and external threads on the plastic tubular member. The foregoing Abstract is merely a resume of general applications, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A battery terminal connector provides similar connector assemblies for electrodes of similar polarity. Each connector includes a U-shaped collector plate providing spaced and parallel flanges extending to spaced and parallel edges. U-shaped tabs are mounted on each electrode and provide legs which extend up along the outer sides of the associated flanges. Each leg provides an edge in alignment with the edge of the associated flange. An edge weld, extending lengthwise of the associated flange edge, connects the adjacent legs. In one embodiment, the legs are twisted so that their end edges extend lengthwise along the edge of the associated flange. In another embodiment, the legs are not twisted and engage the associated flange along the edge of the legs.

Abstract: Two SCR full-wave center-tapped rectifiers are connected in opposite polarity to battery charging terminals. The proper polarity rectifier is selected by a battery polarity sensing circuit that enables the firing of the SCRs of the proper rectifier. The sensing circuit has two transistors of opposite polarity. The transistor matching the polarity of the battery turns on and enables current to the proper SCR gates. The sensing circuit is controlled by an optical isolator that activates the circuit by shorting the polarized output of a diode bridge connected in the transistors's emitter circuit. This allows the optical isolator to control emitter current of either polarity.

Abstract: A PWM waveform generator generates the digitized waveform which may control an inverter so that the inverter output is pulse width modulated and generates a sine wave after filtering. A frequency controlling means includes a cycle clock cycling an address counter which addresses step data in a ROM, and the ROM data is fed to a PWM counter. This PWM counter has a clock input to reset a flip-flop and the output passes through a polarity switch to obtain the digitized waveform. This frequency controlling means is modified by an amplitude controlling means wherein the PWM counter is clocked at a variable frequency rate to control the width of the pulses directly proportional to the desired effective amplitude of the output waveform. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Abstract: A dielectric strength tester is disclosed for use with high-voltage, high-volt amperage electrical equipment. The step-up transformer has a high-voltage secondary winding which is connected through first and second primary windings of a sensing transformer to first and second test terminals. If an operator should contact the second test terminal, which is at high voltage, this would cause a fault-to-ground current, which is an imbalance on the two primary windings, and hence supply an output on the secondary winding of the sensing transformer. This voltage is rectified and passed through a set point resistor means to trigger a thyristor into conduction. This thyristor is connected to de-energize a triac in series with the primary of the step-up transformer. The sensing is rapid because it is carried out in the high voltage secondary, yet the control is in the lower voltage primary of the step-up transformer.

Abstract: A microprocessor controlled battery charger to charge a battery when the charging current is reduced to zero even though the charger is still connected to the battery. The microprocessor includes a means to read the voltage of the battery and also includes a timer. The voltage of the battery is periodically read and when it decreases below a predetermined value the microprocessor again establishes recharging of the battery first at an intermediate rate until either a maximum voltage is reached or a minimum dv/dt is reached and then the current is reduced to a lower current rate for a finishing charge of the battery for a given period of time.

Abstract: A dispenser is provided to dispense laminations to a forward position whereat they may readily be manually grasped for withdrawal from a dispenser and insertion into a preformed coil. One or more laminations may be dispensed in a selected group of laminations so that this entire selected group may be withdrawn at one time and need not be separately manipulated to align those laminations before they can be inserted into the coil. When the laminations are withdrawn from the forward dispensing position, a proximity sensor senses the absence of such laminations and controls an actuator to transversely move laminations from the bottom of the stack of laminations in the dispenser to the forward position, ready to be withdrawn by the operator, and then the actuator withdraws to the rearward position. Abutment means are axially adjustable to select one, two or more laminations in the selected group of laminations being dispensed to the forward position.

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: A spark suppression circuit for a battery charger includes a large filter capacitor connected in series with a semiconductor switch across the terminals of the battery charger. The battery charger does not have any output voltage even though the input is energized because the circuit includes a device to delay supplying of voltage until after the charger output terminals are connected to a battery to be charged. The semiconductor switch is non-conductive until the battery charger output terminals are actually connected to the battery to be charged. At this time, a bias circuit connected across the charger output terminals supplies a bias to turn on the semiconductor switch so that only at that time is the filter capacitor connected across the charger output terminals, and hence this suppresses the possibility of a spark upon connection of the charger output terminals to the battery to be charged.

Abstract: An inverter circuit is disclosed in which the alternating current output is rectified to become a DC power supply with a regulated output voltage. The inverter is controlled to limit the peak current conducted by the power semiconductors and a current limit circuit is provided to limit the DC output current. The invention provides an output current sensing circuit utilizing a current transformer, with the primary winding thereof connected in the alternating current portion of the inverter circuit and with current flow in the primary winding proportional to the DC output. Rectifier means is provided to rectify the output of the secondary winding of the current transformer, and this is supplied across a first resistor. There is means to sample the voltage across this first resistor only during the conduction period of the power semiconductors. An integrating means is provided to integrate the sampled voltage and develop an output current signal for control of the output current from the inverter circuit.

Abstract: A circuit for providing a regulated square wave output voltage and a regulated DC output voltage or both. An AC source energizes a switching circuit, having a variable switching rate, which connects a capacitor in voltage clamping relationship to an AC load for both half cycles of the AC voltage thereacross. This switching rate is controlled in accordance with the time accumulation of an electrical quantity, in the present instance the voltage across the AC load. The DC voltage across the capacitor attains a predetermined equilibrium value when the frequency of the AC output voltage is equal to the frequency of the AC source. If the DC capacitor voltage and the AC output voltage derived therefrom deviate from their equilibrium values, as, for example, because of a change in the level of load current, there occur transient changes in the switching rate of the switching circuit which result in changes in the phase displacement between the AC input voltage and the AC output voltage.