Showing papers on "Electrical network published in 1971"

Fault locating system for electrical circuits

Abstract: A fault locating system for electrical circuits consisting of three major components, a fault sensor, a control circuit or channel, and an indicating device. The fault sensors indicate an abnormal current flow when a fault occurs and transmit the information through the control circuit or channel to the indicating device which in turn displays the information. The control circuit connects the fault sensors in series or parallel, and the sensors are oriented in spaced relationship along the cable or electrical circuit being monitored so that fault detection between adjacent sensors is determined by the indicating device. The system may be set up for automatic resetting. The preferred sensor is a magnetic reed switch, and the fault indicator preferably incorporates a circuit with fast response.

System for preventing erroneous data output signals from an electrical keyboard

Abstract: In a mechanically operated keyboard employing keys each having a multiplicity of electrical switch contacts for providing an encoded electrical signal output corresponding to and uniquely identifying individual key stations, an electrical circuit provides a dummy load across the multiple switch contacts which varies as different keys are actuated in a manner to provide a constant load across the multiple switch contacts The electrical circuit develops a control signal which can be employed in conjunction with associated circuits to inhibit erroneous data output signals from the keyboard in the event of improper switch closure

A New Approach to Analysis and Design of Electromechanical Filters by Finite‐Element Technique

Abstract: Finite‐element method was originally developed for analyzing structures such as beams and shells. A flexure‐type composite vibrator has been used as an example to illustrate the application of this method to vibration problems involving coupled mechanical and electrical systems [Y. Kagawa and G. M. L. Gladwell, IEEE Trans. Sonics Ultrasonics SU‐17, No. 1, 41–49 (1970); J. Acoust. Soc. Japan 26, No. 3, 117–128 (1970)]. This paper develops and adapts this method for the analysis of electromechanical filters of complex shape and construction. The transmission characteristics of a filter are calculated directly without employing the usual method of an equivalent electrical circuit. Two examples of analysis are introduced for presentation. In the first one, the input and output electrodes are set up on the transducers of a composite vibrator, while in the second, two vibrators are coupled by a pair of bars.

Radiation responsive signal storage device

Abstract: Incident radiation (write-in radiation) is directed to a metal-insulator-semiconductor sandwich which defines a photo-detector in electrical circuit with electrical charge storage means, so that the amount of charge stored by the sandwich is changed, causing a change in the electrical response of the sandwich to other radiation (read-out radiation) directed thereto. Thus, invormation represented by the write-in radiation is stored by the sandwich and later this stored information is read out by noting the electrical response to the read-out radiation.

Mathematical aspects of electrical network analysis

Abstract: : The volume constitutes the final scientific report for a symposium on Mathematical Aspects of Electrical Network Theory. It contains thirteen papers presented during the April 1969 meeting of the American Mathematical Society. Topics covered include numerical techniques for nonlinear circuit analysis, network models, perturbation theory for nonlinear network synthesis, and graph theoretic applications to electrical network theory. (Author)

Equivalent electrical circuits of interdigital transducers for piezoelectric generation and detection of Rayleigh waves

Abstract: Experimental and theoretical studies of the generation and detection of Rayleigh waves by arrays of interdigital electrodes deposited on piezoelectric ceramics are described. Experiments with transient voltages suggest that such a transducer can be represented by a 1-dimensional equivalent electrical circuit based on that conventionally used for a bulk-wave transducer, incorporating tranmission lines and piezoelectric transformers. More detailed studies lead to the adoption of a model in which each electrode is represented by the ciruit of a bulk-wave transducer of width one-third of the spatial period of the array. This circuit is used in studies of three important characteristics: the continuous-wave radiation resistance of an array, the continuous-wave voltage transfer from a generating array to a detecting array, and the detector waveform resulting from a transient generating voltage. The circuit is shown to be capable of dealing simultaneously with all three situations more accurately than circuits previously proposed.

Electrical drive motor protective means

Abstract: An electrical drive motor for the compressor of a vapor compression cycle refrigeration system is protected against failure otherwise possibly occurring due to excessively frequent starting by the combination therewith of a two terminal electrical network which delays energization of the electrical drive motor for a predetermined interval of time.

Thermal protection device for linear motor

Abstract: Thermal protection apparatus is disclosed for electrical motors and, in particular, for a linear motor as, for example, the type used in magnetic disc recording drive systems. An electrical circuit, the analog of the thermal characteristics of the armature coil, provides electrical signals indicative of the temperature of the armature coil. Safety or protection means responsive to these electrical signals maintains the motor armature coil below a safe, predetermined level, by, in the preferred embodiment, reducing the average power input to the motor.

Calculation of electric circuits in magnetohydrodynamic problems

Abstract: A NON-ITERATIVE method of solving the electrical engineering equations of the external circuit, compatible with the electromagnetic field equations in one-dimensional magnetohydrodynamic problems, is constructed using the example of a heavy discharge in a plasma. In the solution of various problems of magnetohydrodynamics (the flows in magnetohydrodynamic channels, the electrodynamic acceleration of a plasma, the electrical explosion of conductors etc), one of the essential elements is allowing for the external electrical field. Mathematically this means the inclusion in the fundamental system of equations of an additional—the electrical engineering equation of the circuit, which acts as the boundary condition for the electromagnetic part of the problem. In this paper, by using as an example the problem of the electrical explosion of a wire, we have constructed a non-iterative method for the numerical solution of the electrical circuit equation together with the magnetohydrodynamic system of equations. Some of the principles of the construction of the difference equation of the circuit are considered. An additional difference relation, expressing the energy balance of the circuit, was constructed in order to control the course and quality of the calculation.

Sequential least-squares estimation and the electrical-network problem

Abstract: Fundamental relationships existing between the electrical-network problem and least-squares estimation theory are illustrated, and the theorems of least power associated with the equilibrium conditions of physical systems are shown to correspond to the mathematical concepts of least-squares theory. The solution of the electrical-network problem based on Kron's method of tearing and interconnection is considered, and is shown to incorporate an iterative technique which also forms the basis for sequential least-squares data fitting.

Single pulse test circuit

Abstract: A single pulse test circuit for separating, upon the operation of an electrical switch, a single electrical pulse from a series of electrical pulses simultaneously applied to the clock pulse input terminal of each of two J-K flip-flop circuits The Q and Q output terminals of the first J-K flip-flop circuit are connected to the J and K input terminals, respectively, of the second J-K flip-flop circuit Circuitry, including the electrical switch, is provided for applying a logic ''''one'''' electrical signal to a selected one of the input terminals and a logic ''''zero'''' electrical signal to the other input terminal of the first J-K flip-flop circuit and, upon the operation of the electrical switch, for reversing the electrical signals applied to each one of the input terminals NAND gate logic circuitry responsive to the same logic electrical signal upon each the Q output terminal of the first J-K flip-flop circuit and the Q output terminal of the second J-K flip-flop circuit and one of the series of electrical pulses is provided for producing a single output electrical pulse of a magnitude and width equal to the magnitude and width of the pulses of the series of electrical pulses upon the operation of the electrical switch

Analytical modeling of respiratory protective devices.

Abstract: An analytical description of a generalized respiratory protective device is developed by representing the physical system as an equivalent electrical circuit. As a first step, a system of nomenclature is presented which divides the generalized respiratory protective device into several subsystems, and identifies the possible individual components in each subsystem. Each component is then modeled by its electrical analog, and by combining the appropriate components an electrical analog to a particular respirator system is generated. To evaluate the validity of this generalized analytical model, the U.S. Army M-17 protective mask is modeled, using data obtained through an experimental testing program. The model is analyzed mathematically, with a digital computer employed as necessary, and its accuracy is evaluated by comparing the behavior of the M-17 respirator system, as predicted by the model, to actual system behavior obtained experimentally.

Proceeding of construction of an electrical network

Abstract: An electrical power supply network having a main power supply line extending from a power supply station to consumer or distributing stations according to a predetermined geometrical configuration designed to result in the distribution of electricity in the most economical manner.

Series-parallel electrical circuit

Abstract: A direct current electrical circuit in which any number of electrical devices may be energized in parallel with each other to momentarily provide a higher state of energization of the devices, or in which the devices may be energized in series with each other to provide a lower state of energization of the devices, with the circuit automatically reverting from the parallel energization state to the series energization state. The invention is shown embodied in a trip coil circuit for a multi-pole electrical circuit breaker, such as a three-pole circuit breaker, in which each pole of the circuit breaker is provided with its own separate trip coil, including capacitor means in circuit with each respective trip coil whereby to place each respective trip coil electrically in parallel with the other trip coils across the direct current potential when the trip circuit is initially energized for tripping operation, and additional circuit means connecting the trip coils in series with each other across the direct current potential to provide an alternative current flow path for the trip coils when the capacitor means become substantially fully charged, and also to provide a series path through the trip coils whereby a supervisory signal device may monitor for trip circuit continuity prior to initiation of a tripping operation. The circuit thereby combines the advantages of the fast response time characteristic of a parallel circuit with the supervisory capability of a series circuit for monitoring circuit continuity of the plurality of trip coils.

Reply: Calculation of the transient response of lumped linear systems from their frequency response

Abstract: In the design of systems by frequency-response methods, it is frequently necessary to evaluate the transient response corresponding to a given frequency response. The program presents a method of performing the calculation which gives improved accuracy over other methods due to a new form of approximation of the asympototic behaviour of the frequency response and which is in a form suitable for implementation on a digital computer. An ALGOL program for the calculation is included, and an example of its use is presented.

An electrical contour integrator

Abstract: A simple electrical system capable of evaluating the contour integrals involved in the transformations between Laplace (frequency) and time domains as developed by the authors is described in this paper. Given the frequency response data of a fixed-parameter linear system, its transient response can be evaluated using this integral analyser. In addition to being useful in such domain transformations this instrument can also be used for Fourier coefficient analysis of periodic functions.

Variable resistance control using mercury contact

Abstract: A variable electrical resistance device such as a potentiometer, rheostat or the like, containing spaced electrical resistive and conductive elements having terminals for connection to an external electrical circuit, and a contact of electrically conductive liquid, such as mercury, which spans the elements to provide a current path between the elements and is confined for relative movement along the elements to vary the electrical resistance between the terminals. In the disclosed embodiment, the resistive and conductive elements are carried by a rotor which is rotatable to effect movement of the elements past the mercury contact.

Separation technique for repetitive analysis of electrical networks

Abstract: A matrix technique for the repetitive analysis of electrical networks by interconnecting variable network elements with an intermediate fixed solution for the remainder of the network is described.