Abstract: A self-referencing sensing and control apparatus which may be used advantageously in any industrial installation in which an A.C. powered device, such as the down-hole motor in a submersible pumping system or a plunger relay, is remotely located and in which it is desired (i) to monitor certain parameters, such as temperature and pressure, and/or (ii) to control certain operational functions, such as the state of flow valves and latching means, at the remote site. The power cable used to carry A.C. power to the remotely operating device is also used to carry instrumentation and control signals from local control and readout equipment to an instrumentation package installed at the remote site. The present invention comprises switching means to selectively couple and decouple one or more sensors (or control means) in the instrumentation package to and from the A.C. operating device and the power cable, thereby permitting high voltage testing of the A.C. device and cable, or other tests.

Abstract: An electric branch-line combiner is disclosed by which double power at double voltage is obtainable from two branch-line outlets of a typical existing branch-line circuit interconnected to a typical three-wire electric power source and by which electrical grounding means are readily, conveniently and safely obtained directly from two such existing branch outlets, each having only two contactors.

Abstract: Two P-channel MOS devices and two N-channel MOS devices are interconnected in a manner to provide a polarity reversal circuit. The circuit contains two input terminals and two output terminals. One of the output terminals is designated as a positive terminal while the other is designated as a negative terminal. Regardless of the polarity of voltage supplied to the input terminals, the positive voltage will always appear on the positive output terminal while the negative voltage will always appear on the negative output terminal.

Abstract: A solid state, reverse power flow detector and control circuit which samples the line voltage and current, once each cycle. The voltage sampling circuit includes a pulse generator providing a voltage pulse of short duration at a given time or phase angle in each cycle. The voltage signals are applied to an SCR through a gate operated by the current signals. With forward or no current the voltage signals do not reach the SCR. When current reverses the voltage signals are allowed to trigger the SCR. The SCR turns on a transistor energizing a relay, after a brief delay. The relay acts to set the regulator or other device in power reverse condition. When current again is forward the relay is deenergized and the device returned to the power forward condition.

Abstract: Disclosed is a circuit for converting a current input of either polarity to a low voltage output of a single polarity. The circuit includes two pairs of pnp-npn transistors which are coupled to that current flow in one direction will turn on one pair while the other is reverse biased, and the same polarity will appear at the output regardless of the polarity of the input. The low voltage at the output is established by the voltage drop across the transistors of the pair which are conducting. The circuit is particularly suited for converting telephone line current to a voltage output of 1.5 volts or less.

Abstract: A three-phase motor system is described incorporating a small fractional horsepower three-phase control motor that is connected to rotate in a predetermined direction when a three-phase drive motor is rotating in a predetermined direction. A plurality of microswitches having actuating arms with cam follower portions are mounted with the arms contacting a cam plate. When the system is energized, the cam plate is rotated to open the microswitches if the rotation of the fractional horsepower motor is reversed. The microswitches, when opened, de-energize the fractional horsepower motor and concurrently prevent the closure of a solenoid-operated start switch to prevent energization of the drive motor.

Abstract: A cargo loading and unloading shutoff system is used to control transfer of loads between a cargo aircraft and a loading dock. Control logic means compares commands entered on a control console and the existing conditions in the aircraft and on the dock during a loading or unloading operation. On loading, the logic means shuts off the dock conveyor drive immediately when all loads are transferred to selected aircraft positions and then shuts off the aircraft conveyor drive a predetermined period later. On unloading, the logic means shuts off both the aircraft and dock conveyor drives simultaneously when all loads are transferred to selected dock positions. The logic means also prevents energization of the aircraft and dock conveyor drives when the number of load positions selected in the aircraft is different from the number of load positions selected on the dock.

Abstract: A protective device for portable transceivers to assure that improper polarity is not applied to the power input. Two relays, oppositely polarized from each other by use of diodes, sense the applied power polarity and connect that power so that the power applied to the transceivers is always correct.

Abstract: A common bus energization system is disclosed with first and second bus conductors across which a plurality of individual loads may be connected in parallel. Each of the loads is inductive and is capable of operating on direct current, for example, universal or shunt field DC motors, permanent magnet motors, magnetic particle clutches, eddy current clutches, relays, solenoids and the like. Voltage source means is provided to supply a resultant voltage to the first and second bus conductors. This voltage source means includes first and second sources with the first source connected to supply a large, positive voltage on the first conductor and the second source connected to supply a negative voltage on the first conductor. These two voltage sources are alternated with the first source effective a greater period of time for a net average polarity of positive on the first conductor. Each load, such as a motor, has a controllable semi-conductor connected to it to control the current through the motor.

Abstract: The phase sequence of a three-phase AC power supply is detected and information representing that sequence is stored in a memory device, such as a flip-flop. Since the power supply, once it is energized, may require a few seconds to stabilize (such as may be the case when the power source is a diesel generator), the information fed to the memory device is likely to change during the stabilizing period. At the end of that period, however, the stored information represents the true phase sequence of the AC power supply, and at that time the information is read out and used to actuate switching apparatus to interconnect the three-phase AC power supply to the three terminals of a phase-sensitive load (such as a three-phase AC motor) in the manner necessary to provide the load with a desired phase rotation sequence.

Abstract: An electrical load is energized from an energy source that may not have the capacity to carry the load directly. More specifically, a capacitor is charged at a low charge current for a relatively long period of time and when the load is to be energized, the capacitor is discharged through the load in a relatively short period of time. Current limiting devices protect the power source. The charge and discharge intervals are initiated in response to polarity reversals of the power source. When the power source presents one polarity, the capacitor is charged; and in response to a polarity reversal, the capacitor is discharged through the load. A plurality of capacitors and associated load circuits may be connected to a single power source without feedback between the circuits. A current limiting device may be used to limit the initial load current. Typically, the load may comprise a plurality of lamps, horns, bells or buzzers to indicate an alarm condition.

Abstract: An AC power source characterized by the absence of a step-up output transformer is disclosed. The power source, which includes first and second output terminals across which a load is connected, is designed to provide AC power at a desired output voltage, e.g., 130v rms up to a desired current rating, e.g., 8 amperes. The source includes a first unit which includes a first voltage amplifier associated with positive and negative current amplifiers of substantially unity voltage gain, which provide power at the first output terminal up to the rated current at a voltage of 65v rms. Direct feedback is provided to the first voltage amplifier from the first output terminal, to which the load is connected. The source includes a second unit identical to the first unit, which includes a second voltage amplifier associated with positive and negative current amplifiers of substantially unity voltage gain, which provide power at the second output terminal up to the rated current at a voltage of 65v rms.

Abstract: A remote-controlled circuit breaker apparatus has a pulse generator operable to provide a single output pulse. A change over switch is operable to select the polarity of the pulse applied to a conductor. A circuit breaker device has two electro-magnets arranged to be responsive to conductor pulses of respective opposite polarities to open and close the circuit breaker device. It is arranged that in the absence of a pulse, and with the circuit breaker device open a constant voltage signal appears on the conductor. A visual indicator is responsive to this signal to provide an open-circuit warning. The circuit breaker device also becomes open circuit in response to thermal overload, thereby causing the visual indicator to be energized.

Abstract: A temporary or portable electrical distribution system includes a distribution box supplied with power by a flexible cable. Field repairs carelessly made or other causes may result in wires being transposed or open. To eliminate hazards and to ensure proper operation of equipment, sensing means including simple circuitry in the distribution box prevents operation of a master box switch except upon the verification of proper wiring.

Abstract: Circuitry is utilized to interconnect loads to the power distribution system and only conducts current when voltage conditions from the system are appropriate. Therefore, the load is deenergized whenever reversed connections are made to the power distribution system, or whenever an open circuit exists in any line thereof. Latching means can be included in the circuitry to continually energize the load when an open circuit develops in either nongrounded or hot line of the power distribution system after the load has been initially energized therefrom. Furthermore, the effect of the latching means is externally controlled through a switching means so that remote circuit conditions can be synchronized therewith. When an indicating means is incorporated as the load, the circuitry functions as a detector and when the circuitry is utilized with a circuit breaker to deenergize the load, ground fault protection can be incorporated therewith.