Abstract: A security electrical interrupt device for preventing unauthorized usage of an electrical appliance such as an electric stove, while retaining operation of auxiliary electrical equipment such as the lights and an electrical clock. The device comprises a relay controlled by a micro-processor based programmable controller which measures the amount of electrical supply current being drawn by the appliance. A software computer program stored in the micro-controller commands the relay to disconnect the supply power if any person attempts to operate any part of the appliance which draws electrical current exceeding a preset limit while the controller is in the interrupt mode. The micro controller is programmed to enter the interrupt mode by 1) key sequences entered on a small detachable keypad, 2) when a programmed amount of time has elapsed since the last authorized usage, or 3) by removal of the detachable key pad.

Abstract: An automotive battery charger or other electrical device which draws substantial amounts of power is provided with a variable delay mechanism which prevents turn on of the device when power is applied. The duration of the delay is determined by a random or pseudorandom number generator, so that a plurality of different electrical devices will, in effect, be turned on at random times following application of power. The maximum turn on delay could be conveniently limited to a specific period of time, so that critical operating times of the device, such as the charging cycle of a battery charger, are not shortened excessively.

Abstract: A safety switching device for quickly prohibiting a power source from operating a piece of power equipment and for keeping the power equipment in a stopped state until a manual spring loaded start switch on the safety switching device is depressed. An electromagnetic switch in the safety switching device is arranged to open an AC power circuit to separate the power source from the piece of power equipment in case of power failure, a plug of the high voltage line is pulled from its outlet, an on/off activator switch is switched off or a manual spring loaded stop switch in the safety switching device is depressed. The safety switching device also includes a power convertor connected to the power source by an AC power cord and the on/off activator switch. The power convertor converts an AC voltage a DC voltage for energizing the electromagnetic switch and an electromagnet in a DC circuit of the safety switching device.

Abstract: A simple, inexpensive automatic apparatus for unplugging electrical and electronic equipment from electrical circuits such as power, cable television and telephone circuits when an electrical storm is detected in the vicinity of the device by monitoring conditions that typically change near electric storms and, when one or more indicia of a storm are noted, physically disconnecting the device from the circuit(s) so that substantial insulation is interposed between the device and the circuit(s). In some configurations, re-connection of the electrical or electronic equipment automatically occurs after an electrical storm has passed.

Abstract: The status of a Park/Neutral (P/N) switch for an automatic transmission in an automotive vehicle is diagnosed by a method which includes the steps of determining whether an engine of the automotive vehicle is cranking, diagnosing the P/N switch for a P/N state of the automatic transmission when the engine is cranking, and diagnosing the P/N switch for a Drive state of the automatic transmission when the engine is not cranking.

Abstract: A power source system failing to become operable when only a primary A.C. power source is turned on, and made operable by turning on not only the primary A.C. power source but also a secondary power source is disclosed, in which initial-state-of-secondary-source setting means is previously set so that the initial state of the secondary power source at a time when the primary A.C. power source is turned on, is a desired one of an ON-state and an OFF-state, a system control part reads out the state of the initial-state-of-secondary-source setting means immediately after the primary A.C. power source has been turned on, and an ON-OFF control is performed for an ON/OFF switching circuit in accordance with the read-out state, to make the initial state of the secondary power source equal to the desired state. Thus, in a case where a controlled apparatus is required to become operable as soon as the primary A.C.

Abstract: A wallbox-mountable system for controlling electrical power to a load is disclosed. The system comprises a yoke, a frame, a toggle switch and at least one slidable lever. The yoke has an opening which is completely occupied by the frame member and the frame member has at least one channel. The toggle switch has a its handle extending through the frame and has one end mechanically coupled to a means for turning power on and off to a load. The slidable lever extends through the channel and is mechanically coupled to a means for adjusting the power to a load.

Abstract: A valve for rapidly switching high voltage at high currents includes several identical modules series-coupled between the high voltage rails. Each module includes a three-terminal semiconductor voltage controlled gate turn-off device ("VCGTO"), an input port for receiving a preferably optically coupled gate drive signal, input circuitry, two power switching ports coupled to the VCGTO device output terminals, and an output circuit coupled across the device output terminals. The input circuitry includes an interface circuit and a drive circuit for driving the VCGTO device in response to the gate drive signal, while the output circuit includes a clamping mechanism and regulated clamp voltage circuit that maintains a safe, regulated maximum differential potential across the VCGTO device.

Abstract: In a load control device of the present invention, an operation signal provided by any one of a group of input switches in an operation input section is converted into a serial signal by a signal transmitting section, and the serial signal is applied through a serial signal line to a signal receiving section. In response to the serial signal, the signal receiving section outputs a response signal for driving a load, or a headlamp or a running light. When no response signal is provided, a NAND circuit applies a signal to an automatic lamp control section to automatically control the lighting of the lamp. That is, when the signal transmitting and receiving system becomes out of order, the lighting of the lamps is automatically controlled, which eliminates difficulties encountered when a vehicle is run during night.

Abstract: A two-hand operator's control station mounted on a common enclosure detects an operator's hands and provides output signals without requiring the operator to push buttons. Such control stations, called pushless run bars, are for use with automatic machinery which requires the simultaneous use of two hands to initiate operation of the machinery. In each embodiment of the present invention, two hand-sensing mechanisms are provided on or near the cover of an elongated enclosure, one for sensing each hand. The sensing mechanisms are located sufficiently far apart, near opposite ends of the run bar enclosure, to prevent accidental operation by one hand. Suitable anti-tie-down circuitry, an electrical cover interlock, indicator lights, and physical barriers to prevent access from certain directions may also be provided as part of the apparatus. A first embodiment of the run-bar apparatus employs two separate photo-transceiver units for detecting the operator's two hands.

Abstract: A switched power circuit selectively connects an electrical load to any one of a plurality of branch power circuits. The switched power circuit includes a sensing circuit for sensing electrical loading on each of the branch circuits. A logic circuit is coupled to the sensing circuit for selecting one of the branch circuits to be connected to the load according to the sensed loading to provide balanced loading on each branch circuit.

Abstract: A control for a spa and swimming pool pump and heater assembly with diverter valves, includes a selectively actuable pump and spa heater actuator or relay having a first latching circuit, and having a separate first unlatching switch or relay contact, a selectively actuable pump and pool heater actuator or relay having a second latching circuit including the first unlatching switch or relay contact, and having a second unlatching switch or relay contact in the first latching circuit. The control also includes a diverter valve actuator in parallel to one of the pump and spa heater actuator or relay and pump and pool heater actuator or relay.

Abstract: A switching system includes a module having at least one semiconductor switch for switching current to a load, in particular, a setting member in an automotive control or automatic control device. A short-circuit current monitoring circuit and an idle current monitoring circuit are provided for each semiconductor switch. Each switch may constructed as a multiple-emitter transistor with separate emitter terminals being connected to the respective monitoring circuits whereby load current in the multiple-emitter transistor can be monitored. The short-circuit monitoring circuit outputs a signal indicating excessively large load current in the transistor. The idle monitoring circuit outputs a signal indicating excessively small load current in the transistor.

Abstract: A wallbox-mountable system for controlling electrical power to a load is disclosed. The system comprises a yoke, a frame, a toggle switch and at least one slidable lever. The yoke has an opening which is completely occupied by the frame member and the frame member has at least one channel. The toggle switch has a handle extending through the frame and has one end mechanically coupled to a means for turning power on and off to a load. The slidable lever extends through the channel and is mechanically coupled to a means for adjusting the power to a load.

Abstract: Presented is a device and method for providing a means of driving capacitive cells, such as those comprising suspended particle light valve windows, with a squarewave voltage signal at a select frequency with high efficiency and low power requirements. The invention uses an inductive circuit in parallel with the capacitive load of the capacitive cell, a dc voltage source, and a fast switching means connected to timely control the polarity of the voltage source to the capacitive cell.

Abstract: The apparatus allows the connection of two peripherals to a host device through one port and switching between them. The apparatus includes a sensor for sensing a data signal from the second peripheral device and a switch responsive to the sensor. The switch in a default, first state connects the first peripheral device to the host device and in a second state disconnects the first peripheral device therefrom. If a second peripheral device is connected to the apparatus, the sensor senses a data signal from the device and communicates this sensing to the switch. The switch responds by disconnecting the first device from the host device, leaving the second device solely connected to the host device. If the second peripheral device is disconnected from the apparatus, the switch reconnects the first peripheral device to the host device.

Abstract: A system controls electrical power to multiple loads from both a central location and from local three-way controls. In one embodiment, the system includes means for sensing the power to each load. That sensing capability, in turn, permits the master to set all loads to the same power level, simultaneously, regardless of their original level. The local controls may be standard three-way dimmers or switches.

Abstract: A circuit-breaker including at least one insulating interrupting chamber inside which there are contacts and a blast nozzle. The insulating interrupting chamber is placed on an insulating support containing a drive rod. The circuit-breaker further includes a first terminal and a second terminal. The circuit-breaker has at lest one fluorescent or scintillating optical fiber disposed inside the support and constituting a symmetrical loop around the drive rod. Each end of the fiber is connected to a photodiode equipped with an amplifier. Light propagated in the interrupting chamber, as a result of arcing, reaches the optical fiber loop via a light passage within a terminal of the interrupting chamber remote from the arcing zone within the interrupting chamber.

Abstract: Inputs are programmably interfaced and interlocked with output so that the state of the outputs and the operation of equipment connected thereto depends on the hierarchy or priority (control strategy) which is programmed into the controller. The inputs may be contacts (switch closures) of switches which are thrown to operate HVAC units and high or low limit sensors such as thermostats and pressure sensors of an HVAC system. The outputs operate the motor controls of motors which drive the blowers, fans, pumps, dampers and the like of the HVAC system for environmental control and the safety both of the occupants of a facility and the HVAC equipment therein. The programmable controller has an on-matrix and an off-matrix of switch points which are arranged in columns and rows. Each row of switch points is connected to an input circuit. The columns of switch points in the on-matrix are connected to the outputs via control logic to which each column of switch points is connected.

Abstract: Voltage sensing circuitry monitors the signal input lines of a standard RS232 serial data interface. The voltage levels at the inputs of the interface are compared to known voltages to determine if the correct interconnections have been made between the interfaced devices. If the interconnections are determined to be incorrect, a switching circuit is enabled to correct the faulty connections, and serial data transmission is thereafter initiated.

Abstract: The circuit includes a capacitor (C1) and a resistor (R1) connected in series and interconnected with the switch to sense which phase of the line to which the switch's wiper is connected. The impedance of the series circuit of C1 and R1 is very high, so that when the switch is open, it appears that the wiper is connected with line B, through moderate impedance Z1. (Z1 could be an auxiliary appliance component, e.g. water valve heater relay, or could be simply a resistor). Of course, when the switch is closed, the wiper is connected directly to line A. The monitoring device is referenced to a voltage which is related to the power line by being a dc drop below the instantaneously higher voltage line. The monitoring device thus requires dc isolation from the switch, as well as an input voltage which is substantially less than the line voltage of the power line. DC isolation is provided by C1, while diodes D1 and D2 clamp the signal to acceptable levels.

Abstract: A programmer for controlling the actuation and deactuation of a plurality of load function switches. A motorized cam drum track moves a follower pivoted about a fulcrum pin. A solenoid controlled by a microcomputer slidably moves a bar operable to selectively latch and unlatch the fulcrum pin. When latched, the pin causes the follower to pivot and effect the actuation and deactuation of the associated switch in response to the cam track and the follower, when the fulcrum is unlatched, leaving the switch unmoved. The solenoid controls latching and unlatching independently of the cam drum rotation.

Abstract: An access unit for a local area network with loop topology includes a pair of connectors, a relay circuit, a pair of transformers, a direct current signal extraction circuit, a constant current circuit, a controller, and a coil. With the above arrangement, when a workstation connected to the access unit generates a composite signal having a DC signal, used for driving the relay circuit, superposed onto an AC signal for data transfer, only the DC signal component is extracted by the direct current signal extraction circuit to be inputted into the controller of the access unit. The relay circuit of the access unit is then operated. Thus, the signal outputted from the workstation, the composite signal having the DC signal superposed on the AC signal, is applied to the concentrator, so that the DC signal contained within the composite signal activates the relay contact in the concentrator.

Abstract: In a switch apparatus having a membrane structure, when it is detected that a conductive pattern comes into contact with both of two conductive patterns, it is judged that a normal ON operation is performed, and an ON signal is output. When the conductive pattern comes into contact with only one of the two conductive patterns, it is judged that a failure such as a short-circuit due to peeling occurs, and an alarm signal is output. The switch apparatus has a self-detecting function, so that it reliably detects an unstable condition of a failure such as a short-circuit due to peeling.

Abstract: A control system for a washing machine which controls an induction motor to generate an optimum torque in accordance with a load amount of laundry and whether the washing machine is operating in a washing or drying mode. The control system drives the motor at an optimum torque by varying the input voltage in accordance with the sensed load and sensed mode of operation. This allows a washing machine according to the invention to operate more efficiently and with less noise than conventional washing machines.

Abstract: A two-hand operator's control station mounted on a common enclosure detects an operator's hands and provides output signals without requiring the operator to push buttons. Such control stations, called pushless run bars, are for use with automatic machinery which requires the simultaneous use of two hands to initiate operation of the machinery. In each embodiment of the present invention, two hand-sensing mechanisms are provided on or near the cover of an elongated enclosure, one for sensing each hand. The sensing mechanisms are located sufficiently far apart, near opposite ends of the run bar enclosure, to prevent accidental operation by one hand. Suitable anti-tie-down circuitry, an electrical cover interlock, indicator lights, and physical barriers to prevent access from certain directions may also be provided as part of the apparatus. A first embodiment of the run-bar apparatus employs two separate photo-transceiver units for detecting the operator's two hands.

Abstract: The operation of an electromechanical relay is synchronized with the power line waveform where an electrical power supply is supplied from a source to an electrical load. The current voltage supplied to the load is characterized by a power line waveform. An electromechanical relay is positioned between the power supply and the load where contacts of the relay are opened and closed to interrupt and supply power to the load. A microcontroller is positioned between a power source and the electromechanical relay and actuates the relay so that the contacts are closed or opened at a preselected point on the power line waveform. Closure of the contacts at the preselected point is accelerated by supplying an increased power signal to the relay coil and thereafter returning the signal to the rated power.

Abstract: A clock recovery circuit includes a resonant circuit which is driven into oscillation at a clock frequency by binary 1 pulses in a data signal supplied thereto, a clock signal being derived from the resonant circuit via a buffer and a limiting amplifier. The resonant circuit has a high Q to accommodate long sequences of binary Os during which it is not driven. In order to prevent over-driving when the data signal has a high density of binary 1s, a level detector detects when the oscillation amplitude exceeds a threshold level, whereupon a flip-flop is set to control a gate to inhibit driving of the resonant circuit until its oscillation amplitude has decayed. The flip-flop is clocked by the data signal to operate in synchronism with the incoming data, and may be followed by a second similarly clocked flip-flop to avoid potential errors.

Abstract: A circuit breaker for opening and closing contacts disposed on each phase of a multiphase electric power line has a photo-diode array and a light emitting diode array disposed on opposite sides of a driving rod of a driving mechanism, with a light passing aperture provided in the driving rod. When the aperture in the rod crosses the respective light paths between the photo-diodes and the corresponding light emitting diodes, the photo-diodes issue electric output signals corresponding to movement of the driving rod. By processing these output signals, any abnormal breaking of the breaker contacts among the phases is detected.

Abstract: A dimmer and switch device is adapted for mounting on a wall. The elements of the device that are visible when it is mounted on a wall are easily replaced. In another embodiment, a linear slide dimmer and push-button switch device are arranged in juxtaposition, so that a section of the dimmer slider can pass through the switch mechanism. A high-power, push-button switching device combines a high-power switch and a latching device. A dimmer includes a potentiometer that is marked by detents to permit stable, reproducible dimmer settings. The switching device and dimmer are suitable for use in the dimmer/switch.

Abstract: A visual indication system for easily providing information about the status of the output terminals of a solid state relay. A two-electrode neon glow lamp is connected across the output terminals of the relay in series with a current limiting resistor. The shunting impedance of the relay output terminals prevents voltage from inducing a glow in the neon lamp in certain modes of terminal configuration. When the terminals are ON, neither electrode glows. When the terminals are OFF, both electrodes glow. If the AC relay fails in a half-wave mode, only one of the electrodes will glow.

Abstract: A timed actuator moves the switch mechanism of a conventional wall switch. The actuator is detachably secured to the wall switch in abutting relation thereto. The actuator includes a small electric motor, a programmable timer, and several relays. Linkage, driven by the motor, engages the switch mechanism. The programmable timer drives the relays and the latter controls application of current to the motor. At preset times, current is applied to the motor causing the linkage to move the switch mechanism from one extreme of its travel to the other.

Abstract: An electronic ON/OFF control system for use on a powered hand tool to ensure operator safety and ease of operation. The hand tool is driven either by an electric motor driven, flexible drive shaft or a source of pressurized air supplied to the hand tool through a supply line. A low power frequency is applied alternately to the hand tool and power supply line. Appropriate circuitry detects changes in the frequency of the applied signal caused by an operator grasping the hand tool and power supply line and the sequence in which the two components are grasped. If the hand tool is being grasped when the drive shaft or supply line is subsequently grasped a signal is supplied to a power control unit which actuates the power source for the hand tool. The power control unit maintains the hand tool energized after releasing of the operator's grasp on the on the power supply line and automatically de-energizes the hand tool upon the operator releasing his grasp on the hand tool.

Abstract: Switching equipment for numerically controlled machine tools is provided with at least one controllable switch for initiating a measuring process and a switch control which closes the switch when a supply voltage appears on a connecting wire, for example on a power supply connecting wire of an electric pump for cooling water. Therefore it is possible to measure automatically without any additional program-steps of the central processing unit.

Abstract: The invention is a gas mixture for a diffuse discharge switch which is capable of changing from a conducting state to an insulating state in the presence of electrons upon the introduction of laser light. The mixture is composed of a buffer gas such as nitrogen or argon and an electron attaching gas such as C.sub.6 H.sub.5 SH, C.sub.6 H.sub.5 SCH.sub.3, CH.sub.3 CHO and CF.sub.3 CHO wherein the electron attachment is brought on by indirect excitation of molecules to long-lived states by exposure to laser light.

Abstract: A power adapter for timed control of auxiliary electrical loads is provided for connection between a streetlight fixture or the like and a control module of the fixture. The adapter has a weather-resistant housing and an electrical jumper in the housing extending a power source connection to an input of the module, another jumper returning a control output from the module to a main load of the fixture. An auxiliary socket at the side of the housing powers the auxiliary load, which can be a holiday lighting display. In one version, the adapter has a clock timer for controlling the auxiliary load independently of the main load. In another version, a programmable delay timer, synchronized with commencement of main load operation, terminates operation of the auxiliary load following a predetermined interval of main load operation.

Abstract: This invention is a coin operated switch which may be incorporated into coin operated machines such as video games to reduce cheating of the credit granting feature of the machines. This invention incorporates two electromechanical switches and circuitry which further use the existing machine circuitry to time the travel of a coin between the switches and to grant a credit on the machine only if each switch is tripped and released in the proper order and within the predetermined elapsed time.

Abstract: Electric power switch housed in a housing B, operated manually by a toggle or button I and connected to ends V and W of an electric power cord supplying power to an electrical appliance or apparatus. In the housing B there is a built-in cyclical electronic control timer which when the commutator S is in the "stand-by" position continously stores during a gliding period of time (cycle) the schedule of sequences of on/off power switchings, as commanded by the user by operation of I, into an electronic memory. When the commutator S is in the "simulation" position, operation of the electric power switch is taken over by the electronic control timer, which implements power switchings cyclically and indefinitely according to the schedule of sequences of on/off power switchings stored in said memory during the cycle immediately preceding the transition from the "stand-by" to the "simulation" mode of operation and as long as the commutator S stays in the "simulation" position.

Abstract: A group operated electric circuit disconnect apparatus for a plurality of overhead electric power distribution lines carried on poles. The apparatus includes an elongated extruded base mounted on and extending transversely of a pole. A bracket is connected to an electric circuit component. The elongated base has at least one elongated slot with a reduced dimensioned entry. The bracket is positioned and secured at any position along the base by fasteners having enlarged head portions mating within the slot.

Abstract: A touch operated switch for control of electrical lighting, appliances, machinery and equipment which requires non sparking fail-safe operation. The switch utilizes digital complementary metal oxide semi-conductor technology which requires nearly insignificant standby power and incorporates a unique count down reset circuit which prevents extraneous operation from static discharge, radio frequency (RF) signals or power line transients. The switch will only respond to the electromagnetic flux generated by the power source that the controlled load is connected to. All other signals or pulses of differing frequencies are ignored by the switch thereby preventing inadvertent operation. Due to the limited number of discreet components utilized the total cost of manufacture will be extremely low and is expected to be less than the present manufacturing cost of the standard wall-type light switches that this invention will replace.

Abstract: A protection device, for electronic components of vehicles, having a vehicle battery including a battery terminal with an electrical supply clamp attached thereto, comprising an electrically conductive connector engageable with the battery terminal-clamp combination, a conductor for electrically conductive connector to the electronic components, the device permitting removal of the electrically conductive connector from the terminal-clamp combination, when desired, and an electrically insulative cover to encompass and cover all readily accessible surfaces of the electrically conductive connector and the terminal-clamp combination when the electrically conductive connector is attached thereto.

Abstract: An improved disconnect/ground switch assembly for use in conjunction with a high voltage DC power supply is disclosed. High voltage rectified DC power is provided on a conductor through an insulating bushing. An electrically conductive contacting mechanism mounted on the end of the bushing and in electrical contact with the conductor serves as a source of power for driving a pair of loads through respectively associated switching contact members. Actuating mechanisms for switching either or both of the switch contacts to associated grounded contacts are shown. Opposed apertures in the switch housing are adapted for receiving load driving conductors positioned in conductor conduits. A transparent covering of a viewing aperture for observing the positions of the switch contacts is shown.

Abstract: An electrical switchgear having a position detector that detects the state of actuation of switch contacts and a position detector which judges the locking engagement condition of the switch contacts, wherein these position detectors are connected with an optical control unit by an optical cable.

Abstract: A reclosing system for d-c feeder circuit breakers used on transit systems is disclosed. Circuit breaker closure is prevented when the feeder circuit voltage is in a predetermined voltage range and when the feeder circuit impedance is less than a given value, which is less than the impedance which would be presented by a parked train in a deenergized portion of the transit rails. A Wheatstone bridge is inserted into the circuit during the load impedance measurement. The Wheatstone bridge circuit is compensated for positive or negative rail return voltage. The automatic reclosing scheme is locked out after two closures of the circuit breaker followed by automatic tripping within six minutes, or by twelve load impedance measurements, which are performed within three minutes and which all fail to lead to a circuit breaker closure.

Abstract: A positive space-charge closing switch apparatus for closing electrically the gap between a pair of main electrodes with a positive ion beam that is generated by an ion plasma gun.

Abstract: A power-up circuit is provided for a microprocessor based appliance control which includes a power source providing power between first and second conductors. A first circuit is connected across the conductors and a second circuit is electrically disconnected from one of the conductors and from the power source by a normally open switch. The second circuit includes a microprocessor control and the first circuit includes a relay coil for controlling the normally open switch. An optically coupled solid state relay couples the first and second circuits through a pair of light actuated silicon controlled rectifiers in the first circuit for energizing the relay coil and a pair of light emitting diodes in the second circuit for illuminating the light actuated silicon controlled rectifiers.

Abstract: A vacuum cleaner power and control system wherein a single pair of conductors is employed to transmit electrical power to a remote motor driven agitator and to selectively energize the blower motor of the cleaner. Photo electric means is employed to sense current flow in the conductors and trigger the power switch for the blower in response to the sensing of such flow. A switch includes a load capacitor which may be selectively connected between the conductors to establish current flow therethrough without activating the remote motor driven agitator. In one embodiment, the power supply for the agitator motor is separate from that of the blower and a sensor is provided in the vicinity at which the agitator is connected to sense the supply of power thereto and activate the blower in response to such supply.

Abstract: A reclosing system for d-c feeder breakers in transit systems employing cars using a chopper type of regulated power is disclosed. The circuit includes voltage-sensing and load-measuring circuits which determine that there is no short circuit on the respective feeder line before the circuit breaker can be closed. The system operates in two sequential modes. The first is a voltage-sensing mode which, upon sensing a voltage on the feeder circuit greater than some given magnitude, will cause the closing of the feeder breaker. If this voltage is not sensed during the voltage-sensing mode, the circuit automatically goes into a load-measuring mode wherein a current is injected into the feeder circuit and the voltage drop caused by the injected current is monitored. If a sufficiently high voltage is produced, which indicates that the feeder circuit is free of a fault, the feeder breaker is closed.

Abstract: A protective load disconnect unit is remotely controlled at a single control input terminal from a master controller and monitoring unit. A power switching circuit is actuated to switch a load to be controlled from on to off by a control signal from the master unit. The input terminal is maintained electrically isolated from the switching circuit. A load status response circuit senses the on-off conditions of the power switching circuit. A variable impedance circuit included in the load status response circuit is isolated from the power switching circuit and is connected to the input terminal. The on and off conditions of the power switching circuit changes the variable impedance circuit so that an electrical condition at the input terminal is varied to indicate the load status while the control signal concurrently actuates the switching circuit.

Abstract: A position sensor for a rotatable lamp changer turret having a plurality of lamps which are rotated in sequence to an operating position as the lamps burn out. A circular cam is positioned on the turret that includes a first position indicating portion for each of the lamps for indicating when each of the lamps is in the operating position. The cam includes a second position indicating portion for indicating that all of the lamps have been rotated past the operating position. The second position indicating means is located for stopping the turret in a position with all the lamps out of the operating position for providing a visual alarm indication. A cam follower engages the cam and in turn actuates electrical switch means for controlling rotation of the turret. A third cam portion is positioned between each of the first cam portions for actuating the cam follower and the switch means for maintaining turret rotation until the first cam portions are engaged by the cam follower.