Abstract: A power status monitor for an electronic system includes a charge/discharge model of the system power supply. The charge/discharge model contains an estimate of the amount of time during which energy-storage devices in a system DC power supply are capable of maintaining system operation following loss of AC power. The power status monitor monitors the frequency and an amplitude of the voltage of the AC power source for signs indicating imminent failure of the AC power source. In the event that such signs are detected, the estimate in the charge/discharge model is decremented at a rate corresponding to the rate at which charge is consumed. A trip value, applied to the charge/discharge model, determines the time at which a signal is generated enabling an orderly shutdown of the system load. If acceptable AC power is resumed before the trip value is reached, the charge/discharge model increases its estimate of the time available at a rate corresponding to the charge accumulation in the DC power supply.

Abstract: An uninterruptible power supply including a controlled rectifier for receiving a first AC voltage and for converting the first AC power voltage into a first DC output voltage, a battery for supplying a second DC output voltage, a voltage step-up chopper connected to receive the first DC output voltage and the second DC output voltage as a DC input voltage for stepping up the DC input voltage to produce a stepped-up voltage, and an inverter connected to receive the stepped-up voltage for converting the stepped-up voltage into a second AC voltage which is the AC output of the uninterruptible power supply. Additionally, a method for starting the uninterruptible power supply is disclosed.

Abstract: Switching apparatus for connecting a device requiring a backup power source to a battery bus upon disconnect or failure of the primary power source, without interruption of power, and without loading the backup power source when the device is off. Therefore, the apparatus provides nearly total or complete isolation of the backup source from the load when the device (load) is off.

Abstract: An AC electric supply of a load capable of selectively connecting a main AC power source through a first primary transformer winding or an auxiliary emergency source such as from a battery power supply through a static DC-AC converter through a second primary transformer winding, the load being connected to the secondary transformer winding. The process includes sensing the voltage of the main source and automatically connecting the auxiliary emergency source when low voltage is detected and reconnecting the main source and disconnecting the auxiliary source when the disappearance of the failure of the main source is detected by first causing the auxiliary source frequency to drift, comparing the frequency between the auxiliary source and the resupplied main source, and when the two frequencies are in coincidence, connecting the main source and disconnecting the auxiliary source.

Abstract: The transducer of a demand ink jet is driven by voltage so as to project a droplet of ink from the orifice of an ink chamber on demand. After the chamber of the jet has been filled, an abrupt change in drive voltage level of the transducer disturbs the meniscus of ink in the orifice of the jet so as to move the meniscus away from the chamber. When the meniscus has reached a predetermined position and velocity in the orifice, the drive voltage level supplied to the transducer is substantially changed so as to eject the droplet from the orifice. The change in drive voltage level is contoured so as to minimize high frequency components. An array of ink jets may be similarly driven where the differences from jet to jet are compensated by wave shaping including variations from jet to jet in the period of time between perturbation and the substantial voltage level change leading to droplet projection.

Abstract: For remote feed of a group of electrical users connected in series in a closed loop, a dc voltage is applied to the loop in a polarity opposite to a normal feed voltage in order to determine whether interruptions are present, even if a human body is shunting the loop at the interruption. Each of the users has a diode connected in parallel to its inputs which is polarized such that when the test voltage for creating a test current is applied, substantially only a resistance of the loop is measured exclusive of the users. A loop resistance is determined from a measurement of the test current and the loop resistance is compared to a test resistance set lower than a human body resistance. If the loop resistance is lower than the test resistance, then normal remote feed current is applied to the loop since no interruptions exist.

Abstract: There is provided a control unit for controlling the operation of a fuel valve. The control unit includes a first relay and a second relay. The first relay and the second relay are connectable in series and oppositely actuable. The first relay is actuable in response to a first control signal. The second relay is actuable in response to a second control signal which is inverted with respect to the first control signal. Thus, the relays are differentially operated. Further, there is disclosed a scanner control unit which reduces the noise of a voltage signal whose magnitude is representative of the intensity of a monitored flame in a boiler. The flame scanner control unit uses a comparator to reduce the noise in the voltage signal. The voltage signal is provided at one input of the comparator and a reference signal is provided at the other input of the comparator. The reference signal is representative of the intensity of noise in the boiler when the monitored flame is out.

Abstract: An arrangement for generating in each switching panel of a multipanel switching facility of an electrical power distribution network a digital operating-state image derived from command inputs and switching position signals. The digital operating state image is transmitted to a collecting memory arranged in a coupling panel which produces an overall image of all switching panels; which overall image is transmitted to the individual switching panels at periodic time intervals. A checking procedure is then conducted in the individual switching panels using the overall image. The arrangement utilizes microprocessors which are coupled to one another so as to exchange data via several transmission paths which are one-bit wide. This arrangement obviates the need for an interlock cable harness in the switching panels and cross-cabling between the switching panels.

Abstract: A system and method of electrically interconnecting a multiplicity of electrical lighting fixtures is disclosed in which up to three phase AC power and up to five conductors (i.e., one conductor for each phase, a ground conductor, and a neutral conductor) is used in such manner that selected groups or branches of the lighting fixtures may be independently, selectively controlled, and such that wiring to the fixtures and control switches may be readily plugged into place.

Abstract: An ink jet recording apparatus comprises an ink jet head section constructed with a plurality of pre-divided, discrete ink jet heads, a drive control section and a wiring section, and a common supporting member, on which these ink jet head section, drive control section, and wiring section are disposed and electrically connected each other.

Abstract: A power management system for a recreational vehicle which operates automatically to disconnect a major electrical appliance, such as an air conditioner, heater or water heater, from power when the current drawn by additional appliances exceeds a preset current threshold. When the current drawn by these additional appliances falls below the threshold, the major appliance is automatically reconnected. A preferred embodiment operates to alternate between two or more air conditioners, heaters, or the like, to ensure that only one is connected to power at any given time, but that both are activated alternately and in sequence to provide efficient use of both air conditioners. In addition, preferred embodiments operate to interrupt operation of the air conditioners whenever the power voltage falls excessively low, and to ensure at least a preselected time delay between the time an air conditioner is stopped and restarted.

Abstract: A switching circuit with a time-delay device comprises a pulse generator, and a counter which receives pulses therefrom. The overflow output of the counter transmits a counter signal after receiving a predetermined number of pulses. The counter is provided with a holding circuit for maintaining the counter signal up to the time of resetting and renewed start of the counting operation. The resetting input of the counter receives a signal either by way of an inverter or directly. The overflow output of the counter is connected with the output of the time delay device, either directly to obtain a delayed start or by way of an inverter to obtain a delayed termination.

Abstract: An electrical apparatus that is adapted to be connected between a source of alternating current supply and a load is designed to achieve automatic correction of hot and neutral lines at the output should the supply lines at the input be reversed, and is arranged to be utilized in connection with a ground wire. To achieve the result, a change-over switch is provided in each of the phase wires and a logic circuit is provided for operating the switch, the logic circuit being arranged to detect a voltage change between one of the phase wires and the ground wire so that when a voltage change is detected, the logic circuit will energize the switch to reverse the connection of the supply lines to the load. Two types of change-over switches are disclosed, one in the form of a relay and the other in the form of solid state triacs.

Abstract: A fail safe mechanism for power operated doors comprises an auxiliary power supply, an electric motor, a self operating clutch to connect the motor to the door's normal drive assembly and a relay/timer circuit to energize the motor in the event of a mains failure to enable the motor to drive the door open.

Abstract: A power supply for a load such as a computer, which is sensitive to power interruptions. A switching regulator is coupled to both the AC power line and a rechargeable battery, and makes automatic transitions between AC operation and battery operation, utilizing a transistor switch and an energy storage transformer coupled to both power sources and to the load. The transistor switch is driven by a variable duty cycle control signal provided by a programmed current feedback circuit responsive to both output voltage and instantaneous switch current. The feedback circuit cuts off the switch each time the peak current through the switch reaches a value corresponding to the desired output voltage--thus improving control loop stability and maintaining a constant peak current through the switch to substantially eliminate ripple. The circuit enables one terminal of the battery to be connected to one terminal of the switching transistor, to minimize noise.

Abstract: An electronic door locking system for an automotive vehicle which locks the vehicle doors when the driver depresses push-button type switches installed at an appropriate position on the outside of an automotive vehicle in accordance with a predetermined code, only after the vehicle has been kept parked in a safe state, e.g. after all the vehicle doors have been closed perfectly and/or when the parking brake has been applied to the vehicle securely or the gear shift lever has been set to Park position securely. The system according to the present invention comprises, in particular, a device for detecting unsafe-park states and another device for disabling the lock command signal in response to the unsafe-park signal from the detecting device, in addition to the conventional electronic door locking system.

Abstract: A process and circuit arrangement for exciting a solenoid coil to operate an iron core. Power from an AC power source is full-wave rectified, and then allowed to flow to a solenoid coil by a switch element located between the full-wave rectification circuit and the solenoid coil, which coil is made electrically conductive only for each short period of time corresponding to the top and its vicinities of the voltage wave-form of the rectified power so that the current is allowed to flow to the solenoid coil. Therefore, no current flows to the solenoid for each period of time corresponding to the trough and its vicinities of voltage wave-form of the rectified power. Thus, excitation and non-excitation of the solenoid is continuously alternated to give a dither effect to the iron core associated with the solenoid coil.

Abstract: A switching circuit in a power supply for switching between a main power source and a standby power source includes gating device operated at the time failure of the main power source occurs to disable the operation of a plurality of MOSFETs which are switched by high frequency clock signals to couple the main power source to a load. When the main power source returns, the gating device switches the MOSFETs in synchronization with the power signals supplied by the main power source. The circuit includes a transformer operated by the high frequency clock signals to switch the MOSFETs, enabling the transfer of the power signals from the main source to the standby source to occur at the time the main power source fails.

Abstract: A power factor controller for alternating current/direct current drilling rigs is provided which utilizes a uniquely controlled, unloaded, over-excited generator to provide reactive power to maintain the rig's power factor within prescribed limits during peak demand operations.

Abstract: A back-up voltage source useful over a comparatively long time interval during a power outage or voltage fluctuation is described. A circuit for adjusting the position of a voltage difference available at the back-up supply outputs is described. A potential difference appearing at the terminals of a floating voltage source is connected to a reference circuit for generating a voltage reference from the difference of potential. A voltage follower connected to the reference and to a second voltage source is employed to cause the voltage follower to reposition the potential difference of the supply so as to force the voltage reference to a level equal to the second voltage source.