Abstract: An A.C. overload current sensing, remote power controller of minimum size and weight and integral construction. Current rate sensing wound toroids are used that are small enough to fit around the line terminal studs without having to enlarge the prior insulator space available therein. The electronic overload current detecting and tripping control circuit is replaced by a pair of modules, detector and control modules, having improved performance and a shape and size such that they fit within the relay housing alongside its operating magnet. The detector module has integrator means for converting current rate of change signals into current magnitude indicative signals thereby enabling use therewith of rate sensing wound toroids of about one-tenth the size of equivalent current transformer wound toroids.

Abstract: An auxiliary add-on attachment is disclosed for use in combination with an existing rocker switch. The attachment includes a spring loaded latch mechanism which upon release drives the rocker button to an OFF position. The latch mechanism is released upon retraction of a solenoid plunger when the solenoid is energized by a trip signal which may, for example, be delivered from a timing circuit when a designated machine should be automatically turned off after a certain length of time, such as cathode ray tubes, computers, photocopy machines, etc. Depressing the rocker button back to its ON position loads and resets the latch mechanism.

Abstract: The control system has application to polyphase AC wound rotor motor which employ opposed parallel connected phase controlled thyristors together with series connected fixed resistors in each leg of a delta connected secondary impedance network. The line-to-line secondary terminals of the motor provide a source of polyphase variable frequency and variable amplitude AC reference signals. The variable frequency, variable voltage reference signals are converted into complementary pairs of square wave synchronization voltages. These same reference voltages are also concurrently integrated during their respective positive and negative half cycles to provide complementary pairs of constant peak amplitude, variable frequency voltages which are combined with associated ones of the aforementioned synchronization voltages to provide synchronization locks.

Abstract: A formed pivot structure for a pivotally operable lever mounted in a bushing such as a toggle switch lever bushing. The pivot is provided by a suitable through-hole, opposite blind holes or circular groove in the enlarged portion of the lever into which thin portions of the bushing, either perforated or unperforated, are punched from opposite sides of the bushing. This provides a pair of aligned pivots affording free pivoting of the toggle lever in one plane while retaining it snugly from wobbling out of said plane.

Abstract: A solid state motor control or power control universal assembly means and method whereby common parts are used to provide two basic semiconductor power pole versions, namely, a two-terminal power pole having two semiconductors in reverse-parallel connection between the terminals and a three-terminal power pole having two semiconductors in series connections between two terminals and a third terminal therebetween. These two power pole versions are the requiste subassemblies that may then be connected in various combinations to provide the numerous different types of motor control and power control systems commonly used.

Abstract: A trigger speed control switch for use on portable tools having double-pole contacts with wiping action, larger contact opening gaps, screw-clamp terminals for connection of the power line conductors, a printed circuit board for mounting the speed control circuit, an adjustable trigger lock mechanism with detenting to hold it in adjusted position, and terminals for connecting a load device such as a motor as well as an external filter capacitor. A small version having all of these features is small enough for direct substitution for an on-off trigger switch as well as for universal portable tool application. A larger version having all of these features is adapted for substitution for present wired-components types of trigger speed control switches. In either case, modification of a given tool is not required to receive the double-pole trigger speed control switch.

Abstract: A programmable controller that is programmed to simulate a ladder diagram and accepts input signals to control output devices in accordance with the ladder diagram program and comprising, in addition to a main memory that stores the program, a logic processor and input/output circuits, of a special wire number memory and a control coil memory for receiving, storing and making available to the processor the result of every logic function representing the current on-off status of each wire node and each control coil and associated contacts. This controller affords the maintenance of a complete current record of the changing status of the contacts and their interconnecting circuit nodes. This makes possible a particularly simple unidirectional-logic programming mode because the programmer does not have to keep track of which logic operations must be temporarily stored.

Abstract: An electromagnetic relay is provided with a high current "boost" coil, a lower current normal operating or "seal" coil and a static, electronic circuit that functions under low voltage conditions to energize the boost coil to retain the relay closed. An additional function of this static, electronic circuit is to energize the boost coil for a time interval on initial power application in order to assist in closing the relay, and this time interval automatically varies in the correct direction with variation in the supply voltage available to the coil so that the lower such available voltage is from its normal value, the longer the boosting time interval. At other times, both coils are energized in series at low current to hold the relay closed. This static, electronic circuit is small enough to be integrally incorporated within the housing of a conventional sealed power relay.

Abstract: A two-bimetal thermostat provides double motion for enhanced contact actuation and minimum differential. Two bimetal plates are pivotally supported at one end to extend generally parallel. The other, deflectable ends of these bimetal plates, one of which is shorter than the other, have right-angle bends and are biased by a compression C-spring for overcenter snap-action. These deflectable ends are coupled by drive pins to respective contacts of a spring-biased contact pair to be free of the bimetal plates when closed and are actuated thereby to open condition. Differential adjustment is accomplished by adjusting one bimetal plate longitudinally to vary the C-spring load thereby to correspondingly vary the temperature differential between contact closure and opening. Range adjustment is attained by turning a knob which acts through a cam on the pivotal mounts to vary the angle between the bimetal plates thereby to require more or less bimetal bending for contact actuation.

Abstract: A preassembled self-contained fiber optic module is disclosed which may be inserted in standard switch enclosures to enable a remote electrical switching function to be performed by means of optical switching within the switch enclosure. A single module mounts facing ends of two fiber optic cables in spaced substantially colinear alignment and also forms a narrow elongated guiding channel perpendicular to the colinear axis of the cables and intersecting the gap therebetween for guiding an operator-driven opaque shutter which is movable into the gap to block the optical path between the facing ends of the cables. Transducer means are provided at the remote ends of the fiber optic cables to supply an electrical signal in response to optical transmission. A fiber optic limit switch and a fiber optic pushbutton switch are specifically disclosed.

Abstract: A half wave and full wave energization system for permanent magnet D.C. motors employing a hand trigger operated switch which commutates terminals of a full wave rectifier bridge when connected to a source of A.C. supply to provide selectively half wave and full wave energization of such motors when the trigger is depressed from an extended "off" position.

Abstract: A ground fault interrupter for two and three wire, single phase load circuits employing a circuit breaker having an electro-responsive contact trip-open mechanism, a fault sensing differential transformer, an operational amplifier providing characteristic output pulses whose magnitude depends upon the non-presence or presence of a ground fault and whether the latter is resistive or reactive in kind, and an energizing circuit for the electro-responsive contact trip-open mechanism including a transistor which is normally held non-conducting in the absence of a ground fault and rendered conducting whenever a resistive ground fault occurs. A capacitor in circuit with the amplifier output and transistor base renders the transistor immune from amplifier pulses characteristic of reactive ground faults. Varistors are included between the load circuit wires to suppress transient voltage surges from falsely inducing nuisance ground fault interrupting action.

Abstract: A gate turn-off device is formed by the integration of a power transistor with a lateral thyristor. The thyristor has a split emission path from its emitter, part of the emitter current completing a regenerative loop to maintain conduction after removal of a gating signal, and the remainder of the emitter current supplying base drive to the power transistor to render the latter conductive. In the ON state of the device, most of the load current flows through the power transistor, with only a small holding current flowing through the thyristor. Because of the low level of holding current, the thyristor is easily turned off by a small negative gating signal, breaking the regenerative loop, thus terminating emitter current whereby there is no base drive for the power transistor and hence the device is OFF.

Abstract: A protective control for the starter and electrical systems of a motor vehicle, including a main relay for controlling the electrical system, and a starter relay for controlling the starter system. Electronic logic is provided for the electrical system which: (1) prevents energization of the main relay if the battery polarity is reversed; (2) if the battery polarity is correct, turns on the main relay when a master switch is closed; and (3) maintains the main relay in an ON condition when an AC signal from the alternator is sensed even if the masterswitch is subsequently opened. The latter prevents disconnection of the battery from the electrical system while the engine is running.

Abstract: Precision snap switches having improved forms of integral one piece contact support and wire terminal members that reduce electrical heating, enhance the current carrying ratings of such switches, and facilitate the use of larger size wire terminal securing screws.

Abstract: A transducer is disclosed which provides a digital indication of a sensed analog condition without the need of an analog to digital (A/D) converter or a comparator. A condition responsive element having a true abrupt switching characteristic at a known breakover voltage as a function of a condition being sensed is biased by a voltage source preferably supplying a periodic voltage as a known function of time. The point during the voltage source cycle at which the condition responsive element switches to its other state is determined by the sensed condition. Preferably, a clock of known frequency is enabled when the condition responsive element is in one of its states, whereby clock pulses are counted during an interval whose duration is determined by the sensed condition.

Abstract: A speed control subassembly is made by providing a generally flat heat sink plate having a laterally-formed collector strip at its upper edge. A double-sided-adhesive insulator tape strip is stuck to the heat sink, this tape having a hole large enough to receive a thyristor chip so that the thyristor anode contacts the heat sink with solder paste therebetween. Two formed terminal strips extending in opposite directions are stuck to the tape so that one contacts the cathode and the other contacts the gate of the thyristor chip with solder paste therebetween. A chip capacitor is placed across the terminal strips with solder paste therebetween. A small force is applied to the capacitor and then heat is applied to the stack of parts to solder the parts together and to the heat sink and to set the adhesive resin. This subassembly is then placed into a trigger switch housing and connected to the contacts and variable resistor thereof to provide a trigger speed control switch for portable tools.

Abstract: A semiconductor device is disclosed comprising a temperature sensitive thyristor thermally coupled to a power switching thyristor and electrically connected in parallel with the gate of the latter. The temperature sensitive thyristor senses the temperature of the power switching thyristor and automatically responds thereto above a predetermined temperature by shunting the gate current to prevent overheating of the power switching thyristor. The device may additionally include a second temperature sensitive thyristor having a lower switching temperature than the first mentioned thyristor and connected in series with the gate of the power switching thyristor whereby the latter may be triggered into conduction only within a defined temperature range bounded by the switching temperatures of the temperature sensitive thyristors. Normally off and normally on devices are also disclosed.

Abstract: A rocker switch having non-illuminated indicator means comprising a ribbon or sheet member which effectively slides along the interior surface of a rocker cap having a window visually exposing the appropriate indicia on the ribbon as the rocker is pivoted. The ribbon is flexible enough to assume the interior shape of the rocker cap and stiff enough to slide therealong during rocking operation. A window or lens may assume various positions on the rocker cap with appropriate positioning of indicia on the ribbon therebeneath.

Abstract: Ground to neutral fault protection employing dormant oscillators which are only energized and function on the .[.occurance.]. .Iadd.occurrence .Iaddend.of such type of a ground fault. Combined with known types of two and three wire single phase AC ground fault interrupters to provide circuit interruption regardless of which wire is faulted to ground.