Abstract: The invention concerns a system for monitoring the operating condition of a switch by utilizing one or more integrating stages to determine the switching capacity and prevent overstresses. One or more monitoring devices for current, switch action rate, arc quench chamber insulation, contact condition, mechanical condition, operating temperature, or contact voltage are provided, which report the equipment condition, particularly the switching capacity. The sensors are functionally connected with the switchgear drive via a processing stage. The current sensors, together with a counting device, can report the .intg. i.n.dt, i.e. a measure of the stressing of the switch, and in doing so can disable the drive of the equipment. The invention serves the early detection of switchgear which is no longer fully operational, so that these can be replaced before an overstress occurs.

Abstract: Apparatus for effecting the impedance discrimination for use in an automobile comprises a plurality of switches (11-14) mounted on a steering wheel, and a plurality of first impedance elements (15-17) for providing a different impedance in response to the operation of each switch. A second impedance element (131) is coupled through a common slip-ring connection (8, 9) to the first impedance elements for feeding a current from a battery (1) to the first impedance elements (15-17) to generate a potential corresponding to the operation of one of the switches. A transistor (133) provides a horn activating signal when the potential reaches a predetermined value. A resistance network (141-144; 141-142, 150-154) derives a first value corresponding to the first potential and a second value corresponding to the battery potential.

Abstract: The position sensor constitutes a fixed planar board having disposed on the surface serpentine coil structures of relatively low resistance and inductance. The coils are driven in a resonance mode which provides a frequency output according to the position of a moving planar member. The second movable planar board has disposed on the surface thereof planar loop coil structures. The second board is moved in proximity to the first board to vary the resonance characteristics of the first coil according to the position of the second board with respect to the fixed board. In this manner the frequency output of the system is a function of the position of the boards with respect to one another. Other embodiments depict means for compensating the thermal drifts of the frequency with respect to temperature.

Abstract: An arcing fault detector used the thermodynamic conditions created by an arcing fault within a vented electrical equipment enclosure to quickly activate a protective device which causes tripping of the supply circuit breaker(s). A plurality of temperature sensors are located within the enclosure near the top, and a differential pressure sensor is located in the external wall of the enclosure approximately midway between the vents to compare internal and external pressure. The intelligence from the sensors is processed by a fault protector which controls the tripping of the circuit breaker(s).

Abstract: A power supply circuit including A.C. input of either 110 volts or 220 volts coupled to a full diode bridge, across the output of which are provided series connected capacitors across which the desired system operating voltage appears. A voltage-controlled current generator for driving a diac and triac is connected between the input supply and the bridge capacitors. At 110 volt input, the current generator closes the triac and the circuitry operates as a voltage doubler to provide the desired system voltage. At 220 volt input, the triac remains open, and the full bridge and capacitors provide the same desired system voltage.

Abstract: In a switching device for the interior lighting L of a motor vehicle, having a timing element R1 C1 which is controlled by a gate contact switch TK which is opened by closing a vehicle door and which sets on the interior lighting during a certain time lapse after closing the door, a second timing element R2 C2 is provided to be controlled by the closing of the gate contact switch TK and to set off the interior lighting L after a predetermined time interval, when the ignition switch ZS is open. Thereby, the discharge of the vehicle battery is prevented due to the interior lighting L when a door remains inadvertently open, but, when the ignition is turned on, the interior lighting L remains on if a door is open.

Abstract: An anti-theft device for an automotive vehicle in which the starter is grounded to the vehicle frame unless two switches are manipulated by the user. One switch is the key-operated ignition switch. The second switch is connected to an electrical relay to open one side of the grounded starter to turn over the engine.In one embodiment, the second switch is a sensor located in a hidden place in the vehicle. In another embodiment, the second switch is connected between the battery and an electrical accessory that is energized independently of the position of the ignition switch, such as a powered-operated lock, a brake-operated switch or the like. The user must energize the second switch in order to open the connection between the starter and the ground before he can energize the starter by manipulating the key in the ignition switch.In another embodiment of the invention, both sides of the ignition coil and the starter are normally grounded to the frame.

Abstract: A station protector for communication lines includes an electrical conductor formed for connection to the communications lines and affixed to a base member, a grounding means affixed to the base member, an arrester cartridge disposed in an aperture in the base member and a biased resilient member electrically coupling the electrical conductor to a surge voltage arrester or to circuit ground in the absence of the arrester.

Abstract: A H-switch circuit is disclosed for rotationally driving a DC motor in a forward or reverse direction. The H-switch circuit comprises overcurrent-detecting circuits for four output transistors, which are respectively provided in order to detect the output transistor having an overcurrent, a circuit for generating an output signal upon detecting an overcurrent an integrating circuit controlled to be in a charge or discharge state according to the output signal representative of an overcurrent condition, and a circuit for turning off the output transistors when the integrating circuit is in the charge state and setting the integrating circuit to a discharge state. The charge and discharge operations of the integrating circuit are intermittently repeated until the overcurrent condition of the output transistor ends.

Abstract: A temperature controller with a remote sensor having a high temperature cutoff with circuit means to prevent operation of the unit if tampered with to bypass a safety function. A remote sensor has a thermal fuse and diode feeding a pulsating D.C. voltage to a control circuit having a capacitor and an impedance means to which pulsating D.C. is fed. If the sensor unit is bypassed the thermal fuse in the controller burns out to render the controller inoperative.

Abstract: A three electrode gas tube protector has a central electrode and a line electrode positioned on each side, with a gap between each line electrode and the central electrode, the gaps being at a subatmospheric pressure. Connecting to each line electrode, in an axial arrangement, is a ground assembly having two coaxial conductive cups, their bottom ends spaced by a fusible member. A contact member is positioned within the inner cup and has a head and a stem. Around the stem is a compression spring, the stem passing through the bottoms of the cups and the fusible member. The end of the stem extends over the outer surface of the outer cup bottom, as by riveting. The spring is constrained between the bottom of the inner cup and the head of the contact member. On melting of the fusible member, the inner cup moves axially in the outer cup and a radially extending member, such as a flange or other, moves into contact with a ground member in a support structure.

Abstract: Each of a plurality of parallel connected power supplies is controlled by a parallel control circuit which measures the output current from each power supply and compares this output current to the average output current produced by all the power supplies and generates a signal representative of the difference therebetween to drive the output current of the power supply toward the average output current from all power supplies. The structure includes in addition a switch for disconnecting the parallel control circuit of a failed power supply from the system and a booster resistor for assisting in bootstrapping the startup of a given power supply being inserted into parallel with the preexisting parallel connected power supplies.

Abstract: A load control circuit having an input terminal adapted to receive any one of a number of different input voltage signals including signals of at least first and second type. These signals may be, respectively, DC and AC input signals. Control circuits are provided for operation of the load from the input voltage signal. This control circuit includes at least first part responsive only to said input voltage signal being of first type for coupling said signal of first type to the load, and a second part responsive only to the input voltage signal being of second type for coupling the signal of second type to the load.

Abstract: A power system includes an a-c power supply which constitutes a voltage source for a user of d-c current. The a-c power supply is designed to generate an output voltage having a trapezoidal wave form. This is achieved by generating a sinusoidal voltage and then suppressing the waves at a predetermined amplitude to obtain flat-topped voltage waves. The edges of the trapezoidal waves representing the output voltage of the a-c power supply have slopes which equal or exceed the corresponding slopes of a sinusoidal curve having the same maximum amplitude and period as the trapezoidal output voltage. The a-c power supply is further designed to maintain the mean or average value, as well as the maximum value, of its output voltage constant.

Abstract: Protection of the thin gate oxide of MOS field effect transistors from irreversible puncture due to undesired high voltages and currents, generated by electrostatic discharge through handling or otherwise, is provided by a two stage circuit that operates to shunt thousands or tens of volts around the protected transistors. A first stage, employing a thick field effect transistor, protects against the very high voltage. A second stage, employing a thin field effect transistor, protects against lower but still excessive voltage. The protection circuit is formed as part of an integrated circuit chip by surrounding the lead bonding pad to which the protected transistors are connected.

Abstract: A circuit for controlling the level of a liquid in a tank between predetermined limits is disclosed. A low and high probe are provided, each connected in the tank at the desired limit levels, and each connected to a comparator associated therewith. The output of each of the comparators are connected as inputs to an OR gate, which provides the control signal for activating a pump to pump liquid from the tank, and further provides a latching signal to the lower limit comparator, to keep that comparator latched in an off position until the upper limit comparator is triggered by liquid coming into contact with the upper limit probe.

Abstract: A circuit arrangement for protecting a remotely controllable semi-conductor switch which closes to interrupt an alternating current circuit in order to protect against an overload is disclosed in which a flip-flop is connected to control the operation of a current control circuit connected to the output of the semi-conductor switch in the event of an overload or short-circuit condition in the AC circuit. Provision may also be made for transient overload conditions, as well as providing a visual indication of the conducting condition of the semi-conductor switch.

Abstract: A numerically controlled machine tool has a rotatable spindle (10) to which is connected, in the place of the usual cutting tool, a probe (16) for measuring a work surface (25) to be, or having been, machined by a said tool. The probe (16) includes an electric circuit (30) adapted to respond to engagement between the probe (16) and the work surface (25), by disestablishing a signal (26) to a control system (12) and thereby effect measurement of the position of the work surface (25). The circuit (30) is energized by a battery (31) normally disconnected from the circuit (30) and connectable thereto by the control system (12) effecting a transient rotation of the spindle (10). The rotation acts on a centrifugally operated, normally open switch (FIG. 2) arranged within the probe (16). The circuit (30) is arranged to latch the switch in the "on" condition when the transient rotation ceases whereafter the probe (16) is ready for the probing operation.

Abstract: Method and apparatus are provided for an emission controlled current limiting device. The apparatus may control the current thermionically, by cold cathode emission, by photo-emission, or with plasma devices; the common feature being that the current is limited by controlling a series emission process. The apparatus has applications in both power line transmission and distribution networks to protect existing utility equipment and reduce the cost of new equipment.

Abstract: A protector module, or assembly, for telephone lines and similar systems, has line terminals and a ground terminal in the base. The line circuit is between a related pair of line terminals. The line circuit includes part of a line bracket which extends up the side of the housing. The line bracket extends to the outer end of the housing and an aperture in the end of the housing permits access by a test probe to the line bracket. Normally, two line brackets are provided each associated with a pair of line terminals. A ground bracket also extends up the housing, being connected at one end to the ground terminal and having a flange at its other end. Between the outer end of the line bracket and the flange on the ground bracket a back-up or other form of protector member can be positioned.