Abstract: A magnetic tape using as recording medium selected magnetic or non-magnetic material is used for on-line physical and chemical analysis by exposure to selected external agents, physical or chemical, causing permanent alterations in the material, and changes in the magnetic properties of the materials are sensed to read out the recorded information in correlation with the analyzed phenomenon or process for storage, monitoring or control purposes.

Abstract: A commutation circuit for an inverter using an auxiliary source to accumulate the energy for commutation is simplified by assigning to the main diodes mounted in series with the main thyristor of the inverter the role of preventing partial discharge of the storage devices during the commutation process.

Abstract: A low-cost, single-point analog subsystem comprising a pre-amplifier signal conditioner, a dual-slope integration analog-to-digital converter, and a computer interface circuit. The unit is capable of rejecting high common mode voltages while maintaining extremely high system accuracies. The main application for the invention is in interfacing transducer or instrumentation analog data with a digital computer. The interface circuitry allows the computer to select its channel in an asynchronous manner through special controllogic and without the necessity for employing conventional multiplexing equipment.

Abstract: In order to maintain a balanced load between power rectifiers operating in parallel within an uninterruptible power system, individual closed loops are established for regulating the direct current voltage at the output of the rectifiers and an open loop generates a reference voltage for each of such regulations. An operational amplifier is used as a current source to develop a current representative of the load in a particular rectifier. Parallel current dissipating resistors between each rectifier line and a floating potential common to all rectifier lines generates a reference voltage which is proportional to the average of such current dissipations and represents the average rectifier load.

Abstract: Power demand control in a plant facility is improved by allowing the demand limit imposed as a target to be met at the end of a control period to follow the actual demand in the plant. The demand limit is automatically optimized as actual demand fluctuates and it is set in accordance with past history.

Abstract: A magnetic tape using as recording medium selected magnetic or non-magnetic material is used for on-line physical and chemical analysis by exposure to selected external agents, physical or chemical, causing permanent alterations in the material, and change in the magnetic properties of the materials are sensed to read out the recorded information in correlation with the analyzed phenomenon or process for storage, monitoring or control purposes.

Abstract: An energy conservation schedule is followed automatically in response to production activity in a plant facility. The demand of power from the utility company is used as an indicator of actual production activity. The ON/OFF ratio of non-production loads is reduced to conserve energy and such adjustment is automatic in relation to actual demand of power. In one embodiment of the invention, a higher level of constraint is imposed on the non-production loads as soon as the demand has passed a critical threshold downward. In a second embodiment of the invention, control of the demand is installed in the plant in order to meet a demand limit at the end of a period of control involving the production loads as well as non-production loads under constraints. In the latter situation, whenever demand control is ineffective for a full control period to affect switching of the production loads, the system goes to energy conservation with a higher level of constraints applied to the non-production loads.

Abstract: An elongated workpiece is passed through the axis of a cylindrical ultrasonic transducer in a conduit containing solvent agent for ultrasonic cleaning. The cleaning action is performed with liquid solvent in a blanket of saturated vapor maintained by a solvent boiling sump, while the transducer is kept isolated from the vapor by a special compartment communicating only with the atmosphere for air cooling. Vestibules allow an overflow of solvent from the conduit in entry and exit chambers traversed by the workpiece and circulation of condensate is maintained to and from a storage sump of liquid solvent.

Abstract: An encapsulated intrinsic safety electric barrier in which at least one positive temperature coefficient resistance device is embedded in the insulation together with the other electrical components of the module.

Abstract: Pulse width modulation is produced by digital means. Pulse width modulated waves are stored digitally in a memory and retrieved under control of a voltage signal in order to generate a pulse width modulated wave of predetermined pattern for any discrete value of successive desired output voltage levels. Optimal waveforms are selected and stored which extend only for one quadrant but an alteration of the addressing code based on symmetry yields the mirror image of the stored quadrant while sign modification provides symmetry about the abscissa axis. Also, only a single phase is stored and phase shifting by code alteration of the coded information provides the other phases after retrieval.The notches characterizing a particular pattern are stored in the form of a digital representation one level along several possible levels defining subdivisions of a given time interval which is itself a submultiple of the total duration of the stored quandrant.

Abstract: A variable speed static controlled induction motor is voltage regulated under variable frequency by controlling the inverters under constant pulse width while maintaining a constant volt-hertz ratio through the feedback voltage control loop.

Abstract: In a high current power supply controlled by thyristors mounted in antiparallel in the primary of the power transformers, saturation of the transformers is prevented by a detection circuit responsive to an unbalance in such bilateral switch and protective action is automatically triggered. Display is provided to identify the defective bilateral switch.

Abstract: An adjustable current input inverter-induction motor drive using a commutation bridge associated with a common commutating capacitor and four commutating thyristors. Capacitive means is provided for transferring energy during commutation from one main thyristor branch to the next in sequence through the inverter, and a capacitor inputting in a transformer and full wave rectifier bridge is provided coupled to said capacitive means for recuperating excess energy and for restitution thereof into the DC link of the inverter.

Abstract: A strip of material is reacted in situ with a chemical agent so as to create a chemical change affecting the magnetic properties of the material. From past history with the same kind of strip under identical conditions of reactions with the chemical agent, data such as time of exposure, temperature and partial pressure are recorded providing a calibration of any sensed magnetic property changes in such strip. An accurate direct measurement is thus made possible with an identical strip exposed to unknown temperature or partial pressure, by sensing of the degree of magnetization of the strip.

Abstract: An ultrasonic power generator for operation at a one and a half kilowatt power output from a 220 volt, 50 hertz AC line comprising a transducer coil impedance associated with a resonant capacitor, said generator being generally designed for a one kilowatt power output from a 110 volt, 60 hertz AC line. The generator circuit includes at least one thyristor for switching the resonant capacitor terminals and an oscillating circuit having a time basis including said capacitor designed for circulating a high frequency current at the desired ultrasonic operating frequency sufficient to generate one and a half ohmic kilowatts. A small high Q inductance is added to the inductive reactance of said transducer coil for adjustment to the capacitance values of the oscillating circuit.

Abstract: A flowmeter transducer assembly specially designed for high temperature operation includes only dry-coupled elements. A subassembly preassembled before installation on the pipe section consists of a piezoelectric element held between front and backing electrodes. The backing electrode is backed by a contact electrode while leaving a gap therebetween to prevent reflection of acoustic energy back to the rear of the transducer. The subassembly is introduced into a housing clamped directly on a flow section of a pipe, where the pipe wall is an acoustic wave transmitting or receiving window. In a different embodiment the pipe may serve as the front electrode in dry coupling.

Abstract: A bilateral chopper is used between an inverter and the standby battery of an uninterruptible power supply, the battery being charged through rectification of the AC power by the feedback diodes of the inverter under controlled voltage by the chopper, the load being supplied with AC power under controlled voltage by the chopper from the standby battery in case of failure of the AC power supply.

Abstract: A direct current motor control apparatus includes corrective circuit for eliminating the influence of non-linearities on speed regulation as a result of load variations. A summer circuit at the input of the speed regulator algebraically combines signals representing respectively the armature current and voltage to derive a signal representing the counter-electromotive force of the motor. The latter signal is compared in the summer circuit with a signal representing motor speed for supplying a corrective error signal to the speed regulator, thereby to keep the air gap flux constant and provide a speed-load characteristic which is linear in relation to the armature current drop.

Abstract: In differential input DC gain amplifiers with high input impedance, a capacitive attenuator is built-in in order to reduce the amplifying effect on the AC component due to interference by the industrial power lines. Such attenuation is obtained by feeding back through cross capacitors the AC signal at one output to the input on the opposite side so that the ratio of the differential outputs to the differential inputs for the AC component is substantially unity.

Abstract: A cabinet for electrical equipment to be protected from an hostile environment comprising a sealed top section consisting of a vaporization chamber containing trichlorotrifuoroethane, or other suitable working fluid, with the upper surface having a generally recessed polyhedral shape to promote return of condensate at the roof of the vaporization chamber to replenish the liquid in the chamber.