Abstract: In connection with a protective circuit for an electrically driven liquid or water vacuum cleaner it is proposed to utilize the abrupt rise of the vacuum, which is encountered when a blocking element interrupts the connection between the receptacle for the liquid and the motor/blower area. The vacuum rise is detected by a diaphragm-type vacuum governor and used for triggering a lockable flip-flop which then interrupts the current supply of the drive motor. The locked condition can be released only by disconnecting the unit from the mains.

Abstract: An interlock switch for the service door of a computer. The switch prevents power from being automatically resupplied to the computer if the door is opened while power has been interrupted, even if the door is subsequently closed. The interlock switch includes a magnetic reed switch, an electromagnet for closing the reed switch contacts when the power-on switch of the computer is actuated, and a permanent magnet which holds the reed switch contacts closed as long as the service door has not been opened. The reed switch and electromagnet are mounted on the frame of the cabinet of the computer. The permanent magnet is mounted on the edge of the service door adjacent the reed switch. The use of the switch in a security system is also disclosed.

Abstract: An electronic apparatus comprising a power supply device such as a solar cell having at least one electrode for supplying power, a printed circuit board having at least one electrode for inputting the power from the power supply device, and an elastic, electrically conducting connector for connecting the electrode of the power supply device with the electrode of the printed circuit board. The electrically conducting elastic connector is made of silicone rubber containing carbon filler dispersed therein.

Abstract: A lightning arrester having an insulating cylinder which contains resistance elements made of zinc oxide which have a nonlinear voltage-current characteristic are stored. The insulating cylinder is fixed at least one sealing member having passages which connect the inside space of the insulating cylinder with the outside space thereof. These passages are covered with a material adapted to be softened or melted by a heat and are therefore closed in an air-tight manner. The arrester also includes an arc guide for producing arc type spark short-circuit externally of the insulating cylinder due to gas jetted from the passages upon an arc accident in the insulatng cylinder.

Abstract: A method and apparatus for controlling the consumption of electrical current exceeding the total generating capability of an electrical system and for monitoring the charge of a storage battery between maximum and minimum levels and for disconnecting electrical loads in response to the level reaching the minimum.

Abstract: A lightning arrester monitor which consists of an oxygen gas sensor provided in a lightning arrester having a zinc-oxide-type element made of zinc oxide, the main component thereof, and other oxides added thereto, the oxygen gas sensor measures the oxygen concentration of the element which increases as degradation thereof goes on. The monitor makes it possible to assess degradation of the zinc-oxide-type element with ease, without requiring any complicated electrical circuit for detecting leakage current.

Abstract: A surge arrester of modular form, including a metal oxide varistor disk having a coaxial shunt gap located within the disk. The metal oxide varistor disk has a hole located essentially through the center of the disk and includes top and bottom electrode plates having centrally located projections which protrude inwardly of the disk into the hole of the disk, thereby forming a shunt gap within the disk. The module may be used unhoused in under-oil applications or as a component part of a housed arrester. For under-oil applications, the electrode plates are solder sealed to the disk providing a seal preventing oil or moisture from entering the hole in the shunt gap. As an alternate embodiment the surge arrester module may include a series of two or more of such disks stacked between the top and bottom electrode plates.

Abstract: A line protector for a communications circuit. The protector has a three electrode gas tube, the end electrodes of which are connected to the protector's line input terminals. The middle electrode of the tube is connected to the protector's ground terminal. Decoupling devices such as positive temperature coefficient resistors are connected in series between the line input terminals and the protector's equipment terminals. The protector also includes an additional overvoltage arrestor in the form of two diodes connected between the protector's ground terminal and the equipment terminals. The diodes have a lower voltage rating than the gas tube. A conductive clip which is in firm engagement with the protector's ground terminal is used to removably hold the diodes.

Abstract: An automatic switching apparatus is disclosed for a system employing a battery and a charging device. A load is automatically disconnected in response to the decrease in voltage caused by an inactivation of the charging device so that the battery will not be undesirably discharges if the load is not turned off. An override switch is provided to allow the load to draw power even when the charging device is not operating.

Abstract: An overvoltage protection circuit for electronic equipment having tip and ring lines includes a first voltage sensitive switch having first and second teminals. The first terminal of the first switch is connected to the tip line. A second voltage sensitive switch includes first and second terminals. The first terminal of the second switch is connected to the second terminal of the first switch, and the second terminal thereof is connected to the ring line. A third voltage sensitive switch includes first and second terminals. The first terminal of the third switch is connected to the second terminal of the first switch and to the first terminal of the second switch. The second terminal of the third switch is connected to ground potential. The switches are conductive when a respective voltage threshold is exceeded.

Abstract: An X-radiation protection circuit in a television receiver is responsive to both high voltage and high beam current conditions. A first detector is interconnected with an electron beam power source and monitors the beam current therefrom. The first detector produces a first voltage proportional in magnitude to the electron beam current. A second detector monitors a high voltage transformer that produces a potential for operating on the electron beam and the second detector produces a second voltage that is proportional in magnitude to the high voltage potential. A monitoring circuit constantly monitors both the first and second voltages and produces a trigger signal whenever the additive sum of the first and second voltages exceeds a selected magnitude. In this manner, a trigger signal indicates an excessively high combination of electron beam current and high voltage.

Abstract: A method of selectively isolating faulty channels in a parallel electric power system having at least two controllable AC power sources includes the steps of producing a DC content signal representative of the magnitude of DC voltage in an AC output of one of the power sources and producing a differential current signal representative of differential DC current flowing in connected phases of the power sources. The DC content and differential current signals are combined to produce an error signal which is used to control the operation of the first power source, thereby reducing the magnitude of DC voltage in its output. When the error signal exceeds a predetermined threshold level, a trip signal can be produced and used to selectively isolate a failed channel in the power system. Following isolation of the channels, the differential current signal is disabled such that the error signal is only representative of the DC content signal for split channel operation.

Abstract: In a preferred embodiment, a receptacle having multiple electrical outlets includes in the main electrical inlet in electrical series with each of the electrical outlets, a heat-sensitive circuit-breaking element characterized as breaking of electrical circuit passed therethrough when the flow of current exceeds a predetermined amperage, as responsive to increased heat of resistance or other surrounding environmental heat, and as reestablishing circuitry when temperature has cooled-down to at-least a circuit-breaking temperature, there being preferably included in circuit with the circuit-breaking element a conventional electrical time delay element characterized by delaying reestablishing circuitry therethrough whenever circuitry has been broken, with a time delay of sufficient length to permit a cooling of circuitry to a point below circuit-breaking temperature of the circuit-breaking element, to prevent fire hazard from overheated old and/or inadequate house-wiring or insulation thereof.

Abstract: A voltage surge suppression circuit for a low voltage coaxial cable comprises a gas tube connected across the signal and shield conductors and an MOV connecting the shield conductor to a ground. In the case of a balance signal line comprising two conductors, a first gas tube connects one line to ground and a second gas tube is connected across both conductors. A third gas tube may connect the other conductor to ground in which case the second gas tube may be optional. The ground is preferably a ground associated with a power line voltage surge suppression means.

Abstract: When a voltage (V) of a D.C. power source having an internal resistance (5a) exceeds an "exciting voltage" (FIG. 2), transistors (21, 28 and 33) turn ON, and a transistor (30) turns OFF, and then a tripping winding 16 is excited to close a circuit breaker; on the other hand when the voltage (V) is lowered under a "tripping voltage", the transistor (33) turns OFF and the transistor (30) turns ON, and thereby a load resistor (31) which is less than a resistance 34 of the tripping winding 16 is connected to the D.C. power source; consequently, the voltage V is further lowered by the internal resistance (5a), and a voltage difference is produced between the exciting voltage and the tripping voltage, thus making a "hysteresis characteristic" between the exciting voltage and the tripping voltage.

Abstract: A protective PTC device is heated by another PTC device to an elevated temperature greater than ambient but less than its switching temperature. The elevated temperature of the protective PTC device reduces its switching response time, and minimizes variations in such response time with variations in ambient temperature.

Abstract: A motor control device controls a motor driving mechanism which drives a motor according to a motor drive signal for providing a normal drive signal and a locked condition signal. When the motor becomes overloaded while being driven by the motor driving mechanism according to the motor drive signal, the motor driving mechanism is controlled by controlling circuitry which inhibits the motor drive signal from being supplied to the motor driving mechanism. The controlling circuitry, while the motor is in the overloaded state, controls the motor driving mechanism so that power is supplied intermittently to the motor, or so that the supply of power for the regular and reverse rotation is given alternately. The controlling circuitry, when the load of the motor becomes normal, allows driving of the motor according to the motor drive signal.

Abstract: An inverter rectifies an AC input to produce a DC output and switches the DC output so as to selectively obtain a high-frequency output for microwave or induction heating. A microwave heating unit is coupled to the inverter, receives the high-frequency output for microwave heating, and generates a first heating power of a microwave. An induction heating unit is coupled to the inverter, receives the high-frequency output for induction heating, and generates a second heating power of electromagnetic induction. An output setting unit selectively sets an output setting value for the first or second heating power. An input detector detects a current value of the AC input to the inverter.

Abstract: A surge or transient protection circuit is described which operates in an immediate fail-safe mode of failure. If an incoming transient exceeds the transient absorption capacity of the circuit, precision fast-blow fuses are immediately opened to remove current from the load to prevent damage to the equipment connected to the transient suppression circuit and to indicate to the user that the transient suppression abilities of this circuit have been damaged. The transient suppression circuit uses silicon transient voltage suppressor components to absorb the fast-rising edge of transients and also uses slower-acting MOV transient absorption devices for the bulk of the overvoltage transient power. Upon short-circuit failure of any of the suppressor components, the excessive current draw produced thereby results in blowing of the fast-blow fuses.

Abstract: A line protector module device for a communications circuit having a line protector circuit assembly including a base, a frame having a retaining portion, a spring mounted to the base, an arrester and a solder pellet compressibly held between the spring and the retaining portion of the frame. The spring is constructed of a strip of material which is formed in an S-shape. The spring has tabs formed in the material so that when the spring is subjected to a predetermined amount of compressive force, the tabs prevent nonrecoverable compression.