Abstract: A corona discharge element, process for manufacturing the corona discharge element and a corona device including the corona discharge element. The element is a metal strip with peaks on one side thereof alternately positioned in the plane of one side of the strip and then the other with the peaks having the shape of a four-sided pyramid and one side of the pyramid lying in the plane of the surface of the strip. The process includes grinding the teeth of a saw blade to assume pyramidal shape. The corona device includes a frame, a corona discharge element, laminar auxiliary electrodes and grid electrode in which the element, laminar electrodes and grid electrode are electrically insulated from each other and have electrical connections thereto.

Abstract: A self sintering compound tubular electrode suitable particularly for making metal articles by supply of metal with an electroslag process, consisting of a plurality of concentric walls, each pair of said concentric walls defining an annular cavity containing in the melting zone of the electrode a layer of sintered metal powder, and above said sintered layer, a second layer of powder not yet sintered.

Abstract: A solid state oil burner safety control system with integral ignition and particularly adapted for use with a motor powered oil burner, the system providing intermittent ignition, timed safety shutdown, motor starting capability and automatic restart in the event of combustion failure. The system is also adapted to prevent burner motor starting if the line voltage is below a predetermined value.

Abstract: According to one feature a bearing-free oscillation motor, e.g. for driving an optical scanner or chopper comprises a torsion shaft fixed at one end for rotational oscillation about its axis, a rotor support member substantially more rigid in bending than the torsion shaft attached to the free end of the shaft and extending back therealong, a magnetically interactive rotor rigidly joined to the support member at the midlength of the torsion shaft, and a magnetically interactive stator adjacent the rotor for inducing rotational oscillation of the rotor, the torsion shaft and the rotor support member cooperating to provide a stiff system in bending. Preferably the rotor torsion shaft and rotor support member assembly are cooperatively constructed to restrain the rotor, in response to radial forces acting on it, to substantially translational motion without tilting of the rotor or the attached mirror or other device.

Abstract: A circuit interrupter having an associated control system which senses overload current or ground fault current and causes an appropriate tripping of the circuit interrupter. Tripping energy for causing the circuit interrupter to open under a normal fault condition is derived from the fault current itself. In addition, tripping energy for causing the circuit interrupter to open due to a ground fault condition is derived from the ground fault current.

Abstract: A circuit for detecting the level of oil in an oil-collecting chamber conning oil floating on water. A pair of electrodes are disposed in the oil-collecting chamber for detecting the presence of oil therein. A sensing circuit, connected between the electrodes and an amplifier, contains a sensing current when water or air surrounds the electrodes. The amplified sensing current switches a transistor on transmitting a d-c voltage to an open type solenoid valve located in an outlet tube thereby closing the valve.

Abstract: A fault-current limiter is formed as a self-contained unit which can be connected in an existing power transmission system. The fault-current limiter consists of a series-connected inductor and capacitor which are resonant with the power line frequency, and a normally open switch is in parallel with the capacitor. A sodium fuse connected in series with a calibrating impedance is connected in parallel with the switch and the fuse is operated under predetermined circuit current conditions. The sodium fuse extends an operating plunger upon its operation, and the plunger causes the switch to close, thereby to short-circuit the capacitor and connect the current-limiting impedance of the inductor in the main power circuit.

Abstract: A control circuit for the motor of an electric marine toilet which, effectively, causes the toilet to flush. A conventional D.C. source of potential is employed with a conventional marine toilet including a motor, a pump driven by the motor and a macerator driven by the motor. The lid of the toilet operates a normally open switch. An advantage of the invention is that the lid-operated switch prevents injury to the operator. Moreover, the lid-operated switch provides a motor control override. That is, the motor can be turned off whenever the lid is lifted. A control circuit is provided between the source and the motor to control the motor, the lid operating, for example, by a magnet, a reed switch in the control circuit. The flush cycle may extend over any period. However, a three-second flush cycle is typical. The control circuit includes a momentary contact push button to operate the motor for a three-second interval timed by the control circuit.

Abstract: An electric toaster in which a toast support bar is held down by an energized electric magnet so as to maintain bread, on the support bar, alongside electric heating elements. When the bread has been toasted to the desired degree, the electromagnet is de-energized, permitting springs to lift the support bar to pop-up the toast. The rising movement of the support bar causes a switch to operate which interrupts the electrical supply to the elements.

Abstract: The voltage-to-ground or neutral of one phase conductor of a three-phase line is compared with the mesh or interphase voltage of the other two phases on an amplitude basis and the comparison result is used to trigger a threshold switch if the former is much smaller than the latter. The threshold switch may be connected to the selector of an excitation system of a network protection assembly or a nonselective excitation system may utilize the outputs of the threshold switches for each of the three comparisons, in order to produce selective triggering of a network protection assembly.

Abstract: A compensating circuit for a cold junction of a thermocouple includes a sign inverting amplifier, a power source and a summing amplifier. A thermo-electromotive force of the thermocouple, the output of the sign inverting amplifier and the voltage of the power source are applied to one input terminal of the summing amplifier through resistors. An output corresponding to the temperature of the hot junction of the thermocouple is obtained from the output terminal of the summing amplifier.

Abstract: A coolant fluid chamber is affixed to the shell of an electric arc furnace to cool and decrease erosion of the refractory lining of the furnace caused by localized heating and arc flaring. The wall of the cooling chamber adjacent the furnace shell comprises a diaphragm or sheet of flexible material which is subject to deformation when the space between it and the furnace shell is evacuated and the sheet is pressed. The interface between the diaphragm and shell is coated with a flowable or deformable heat conductive material prior to attachment of the chamber to the furnace so that this material will flow into any void spaces in the interface to thereby enhance thermal conduction.

Abstract: A fail-safe timing circuit which includes a variable passive timing element and an active timer or timing device so as to control a device, for example, a fail-safe or B-relay such as is used in railroad signaling.

Abstract: The disclosed horizontally divisible furnace shell comprises a spherically shaped bottom section and truncated cone cover-like shaped middle and top wall sections stacked upon the bottom section, the form of the middle and top sections resulting in barrel-shaped shell walls. Each of the three modular sections has a metal casing with a refractory lining which may be made of firebrick or fireclay. Each wall section has an inwardly projecting ledge at its lower end for supporting the refractory lining. For interconnecting and aligning the sections, tapered locating pins and sockets are provided between all sections. Water-cooled flanges are preferably provided at the upper and lower ends of the top wall section. The joint between the middle and top wall sections is stepped upwardly adjacent the pouring spout so that such joint will be above the level of the molten metal, even when the furnace is tilted to pour out the metal.

Abstract: A power control system is disclosed for an electric arc or refining furnace circuit to which is supplied power directly from an independent power generating unit or units installed independently of a publicly available power supply system or any other power generating unit. Depending upon the operating conditions of the furnace, the power supply is controlled by the suitable adjustment of the generator voltage or frequency or by the combination thereof based upon the relations V = K..PHI..n where V = generator voltage, K = constant, .PHI. = flux density and n = operating speed of a prime mover mechanically coupled to each generator, and f = p.n/60 where f = frequency, and p = number of poles in each generator.

Abstract: The invention concerns a converter arrangement for electrode melting furnaces, particularly for electric slag remelting of metals. A current regulator in the form of a PI controller is associated with the converter arrangement. The former is influenced by an actual current value, a reference current value, and additionally, by a control quantity. The control quantity replaces the current regulation of the regulator by a voltage control in dependence on periodic or aperiodic conditions which may be due to operational causes or to trouble and interfere with the melting process in the furnace. More particularly, for the duration of such conditions, the control quantity causes the output voltage of the regulator, which voltage acts on the control unit feeding the converter, to be limited upward to an adjustable value.

Abstract: A timelock for bank vault doors and the like is disclosed. The disclosed timelock includes three electronic interval timing devices, each interval timing device including a bank of thumbwheel switches on which the desired minimum interval from the arming of the timelock to the reopening of the bank vault door or the like is retained from day to day unless manually changed. All three of the electronic interval timing devices are started by a switch operated by the timelock arming lever. Each electronic interval timing device includes a numerical display device on which the preset delay interval retained in its bank of thumbwheel switches is displayed. Each electronic interval timing device also includes a numerical display on which the unexpired delay duration is displayed in numerical form whenever that interval timing device is operating. Each electronic interval timing device also includes an output solenoid and means for energizing the output solenoid for a predetermined period (e.g.

Abstract: In an electrostatographic copying system, where a common imaging surface is subjected to currents from several corona generators during copying, the actual output current of each corona generator is individually measured, and controlled, utilizing individual current measurement resistive paths between the low voltage sides of discrete power supply circuits provided for each corona generator and a common ground path from the imaging surface, and by individually feeding back the shield current of each corona generator in a feedback path separate from the current measurement path. A.C. lead feedback, and switching and measurement circuitry are also disclosed.

Abstract: An electric furnace for the melting of metallic and non-metallic charge, comprising an annular hearth which houses the electrodes connected to a power supply. The central zone of the furnace can accommodate the spouts for discharging the melt, supports with electrode holders, furnace transformers or gas cleaning devices.

Abstract: A safety interlock system is disclosed for microwave ovens or other high voltage electrical apparatus incorporating sensor means for detecting any malfunction. Means are provided for interrupting line input power or actuating a failure indicating device or a combination of both. Thermally actuated means, such as bimetallic or meltable elements, as well as circuit breakers, relays and fuses are described. The sensor means are associated with each of the interlocks and do not carry regular equipment-load current until such time as a malfunction of the companion interlock occurs. Replacement of the faulty equipment by authorized personnel and manual resetting of the interrupt or indicating means before the oven is energized again reduce the risk of accidental radiation, electrical shock or damage to the apparatus.