Showing papers on "Electrical network published in 1970"

New equivalent circuits for elementary piezoelectric transducers

Abstract: New equivalent circuits, having several advantages over previous circuits, are presented for three types of piezoelectric transducer: the thickness-expander plate, the end-electroded bar and the side-electroded bar. Each of the circuits involves an electrical network of frequency-dependent components connected to the centre of an acoustic transmission line.

Tableau network design system

Abstract: An automated process for network optimization which fully incorporates sparse matrix techniques. The system has further application to any generalized system which may be described mathematically by a set of algebraic and differential equations. Operating on a user input which defines X electrical network, the system generates lists of formated data representing a set of algebraic and differential equations. The variables in the equations are solved for by a process of Crout elimination, and each resulting operation in the Crout algorithm is identified in accordance with one of a plurality of variablility types. Then, a separate Solve program code for each variability type is compiled by the system. The individual Solve programs are then executed in a hierarchical loop sequence during the solution of the network design problem by means of a Newtonian iteration which is expressed as delta A(X)/ delta X Delta X -A(x). Where A(x) represents a tableau vector consisting of a set of algebraic and differential equations for the electrical network.

Circuit continuity monitoring, warning and proving device

Abstract: A circuit continuity and signal warning device for monitoring the continuity of an electrical circuit controlling the activation of a motor vehicle inflatable occupant restraining system. The monitoring warning device is connected by parallel circuit connections to the existing electrical circuit wiring of the vehicle and the electrical control circuit for the air bag system and provides a signal warning in the event of a circuit discontinuity in the electrical energization circuit, including the electrical detonation device, of the air bag system to warn the operator that the circuit is inoperative and the system is defective. The continuity monitoring device further features a signal proving or checking circuit that is operated each time the motor vehicle is started to prove the operability of the warning device.

Overload protection circuit

Abstract: An overload protection circuit employing a transistor circuit responsive to bipolar direct current signals to prevent damage to overloaded electrical circuits. The transistor circuit is responsive to instantaneous current amplitudes in the associated electrical circuit to be protected greater than a predetermined value, to limit the current to a safe value, to thereby prevent damage to various components, such as transistors, of the associated electrical circuit.

Electrical circuit control apparatus

Abstract: Electrical circuit control apparatus and more particularly a spring-loaded contact pin assembly is described for making and breaking electrical circuits, the structure being particularly suited for circuits of railroad cars which are coupled and uncoupled and which cannot have exposed electrically live contact pins.

Programable electric circuit card

Abstract: A flexible selective programable electrical circuit card including a flexible base onto which electrical film components and film connectors are applied An indicia which allows the card to be punched in a manner to program the electrical components of the card

Apparatus for analyzing pipeline networks and computing elements therefor

Abstract: An apparatus for analyzing pipeline networks comprising an electrical circuit system arranged to simulate pipes and loads in a pipeline network comprising a plurality of interconnected computing elements, each connected to represent a pipe, a source of applied voltage connected to the electrical circuit system at a point where a source of pressure is connected to the pipeline network, and variable resistors connected to represent the loads in the system, such that varying voltage drops will occur across the computing elements as the applied voltage varies. Each computing element simulates the variation in fluid flow through a fluid conduit with variation in fluid pressure drop across the conduit over a predetermined range of pressure variation.

Electric network and method of making same

Abstract: An electrical network has a carrier-free, self-supporting grid system prefabricated in one piece of an electrically conductive material. The grid system defines a plurality of electrically conductive paths. A predetermined number of various electrical components are mounted on the grid system in predetermined locations, and predetermined ones of the defined conductive paths are severed. The self-supporting grid system may be constructed as a continuous tape and cut to the desired size; and the predetermined paths may be severed by stamping or cutting.

Algebraic Model of Electrical Network

Abstract: The set of all possible electrical states of a network is modeled using linear algebra and group theory. The model which is the multidimensional linear space is established, described, and verified. The formulas are derived making possible numerical calculations and network analysis. All possible methods of network solution are modeled and discussed using linear transformation theory. The degree of freedom of a network is defined and described. Finally, the classification of networks is proposed as far as topological structures and methods of solution are concerned. The theory developed makes possible a more general approach and solution to power system problems.

Invited Paper Models And Tools For Simulation And Analysis Of Metrorail Transit Systems

Abstract: The traffic and electrical analysis of a metrorail transit system may be successfully performed only by means of simulation tools; an analytical approach is in fact possible only introducing heavy simplifications due to the complexity and the mutual interaction of the phenomena, often non-linear, which determine the behaviour of the system. This is particularly true when the problems of determining a suitable schedule for the train traffic and of sizing the electrical network of an underground railway system are faced. In this paper two different simulators, that can be used to analyze the feasibility and the quality of the solutions to the above two problems, are presented. The first one is a stochastic event-driven simulator which allows the performance analysis of a given schedule and is able to represent the system kinematics and the safety constraints; the second one is an integrated system simulator which allows the electrical analysis of the network during the movement of the trains along the track.

Techniques for circuit analysis (part three): Linear circuit analysis (concluded) Nonlinear analysis

Abstract: A judicious combination of the most suitable of the mathematical techniques now available makes possible the development of a system of programs for analysing electrical circuits which is both more efficient and more accurate than has previously been possible. These improvements are particularly necessary in the field of analogue type circuits, the present requirements for which are not met by existing analysis programs. The first paper, 1 which was introductory, gave a preliminary survey of the whole material. The second paper 2 commenced the detailed description of the techniques of linear analysis. The present paper concludes this description and commences the description of techniques for nonlinear analysis.

Temperature compensation circuit for magnetic core memories

Abstract: An electrical circuit to compensate for the change in electrical characteristics of magnetic cores with changes in ambient temperature. In a magnetic core memory system comprising a common inhibit and sense winding, the resistance of the inhibit-winding circuit used to compensate for increases in temperature and its effect upon the characteristics of the magnetic cores.

Speed reducer and positioning device

Abstract: Two mechanical elements are mounted for independent rotation in the same direction about a common a axis. The difference of the rates of rotation of the two mechanical elements is converted into a resultant mechanical rate of rotation of an output shaft. An electrical element may be mounted on each of the mechanical elements in electrical coactive relationship providing a variable electrical value dependent on the relative angular displacement of the two mechanical elements when the electrical elements are connected into an electrical circuit.

Thermal pollution monitoring device

Abstract: A device for monitoring a particular function such as temperature for determining when the function is above a threshold level. A sensor responsive to the particular function being monitored provides a variable electrical signal in response to variations of the particular function. An electrical circuit is coupled to receive the variable electrical signal at an input. The electrical circuit is in a first state in response to the variable electrical signal above the threshold level and is in a second state in response to the variable electrical signal below the threshold level. A first electrolytic cell is coupled to the input of the electrical circuit and is responsive to the variable electrical signal when the electrical circuit is in the first state. A second electrolytic cell is coupled to the output of the electrical circuit and is responsive to a constant signal when the electrical circuit is in the first state.

Piezo-damping Of Light Structures: Modelling And Experimental Results

Abstract: By including piezomaterials into a light structure, it is possible to convert a part of its vibrational energy into electrical energy. If this electrical energy is addressed to a dissipative impedance, a damping effect is obtained. This paper presents, from modelling results, the performance improvement obtained when the dissipative impedance includes either a negative capacity in order to cancel the capacity of the used piezo-ceramics, or a resonant electrical circuit tuned to the mechanical frequency to be damped. It is shown how the obtained performances are related to a non-dimensional coupling factor between the used piezo-materials and the structure to be damped. Piezo-damping is applied to a blade for isostatic mount of satellite equipment and experimental results are presented. The retained technique is of the tuned circuit type. The obtained results emphasise the performance of the piezodamping, the good correlation with modelling prediction, the low sensitivity to mistuning of the dissipative electrical circuit and its very low power consumption (related to the use of active components for achieving the electrical tuning).

Techniques for circuit analysis (part four): Conclusion

Abstract: A judicious combination of the most suitable of the mathematical techniques now available makes possible the development of a system of programs for analysing electrical circuits which is both more efficient and more accurate than has hitherto been possible. These improvements are particularly necessary in the field of analogue type circuits, the present requirements for which are not met by existing analysis programs. The first paper 1 , which was introductory, gave a preliminary survey of the whole material. The second paper 2 commenced the detailed description of the techniques of linear analysis. Paper three 3 completed the description of linear techniques and commenced an account of the method of steady state nonlinear analysis based on a Picard iteration using the Fast Fourier Transform. The present paper, which ends this series, concludes the description of nonlinear steady state analysis by describing a method of steady state sensitivity analysis. It then considers certain methods of dealing with the problems of transient analysis of nonlinear circuits and concludes by surveying the position which has now been achieved in the field as a whole and discussing some of the problems which remain outstanding.

Applications of Linear Graph Theory to Lumped Models of Solid-State Devices

Abstract: Linear graph theory has received wide application in electrical network theory. This paper extends the well-known methods of network analysis by exploiting the linear relationship between current and carrier density that exists in the lumped (large-signal) model of the bipolar transistor. The lumped model is described briefly and a linear graph is drawn for the lumped model. Relations between the trees and two-trees of this graph and the incrementals ?, Ico, and Ieo are then derived. A lumped model for a double emitter transistor is also considered and its graph is drawn. Linear graphs are then used to determine the lumped parameters of a and reverse currents for two conditions: 1) emitter one as the input and emitter two open circuited and 2) emitter one as the input and emitter two shorted. Each condition leads to its own graph which may then be used to find the applicable a and reverse currents. Methods for determining the circuit parameters are fully outlined and some sample calculations are given.

Switching device with moving parts in the form of a cross

Abstract: An electromagnetic switching device having a built-in unit consisting of a cross-shaped magnetic circuit element adapted to selectively cooperate with the poles of at least two magnetic circuits and having at least one contact element which may be driven by the magnetic circuit element towards one of two positions so as to selectively close at least two corresponding electrical circuits.

Parallel Simulation Of Electrical CircuitsUsing The TLM Technique

Abstract: This paper describes a parallel simulation of an electronic circuit using the Transmission Line Modelling (TLM) method. The TLM method is used to decouple the circuit into sub-circuits which are then simulated concurrently in a parallel processing system. This approach not only simplifies the circuit formulation process but also reduces the overall computing time of the circuit simulation when compared with traditional sequential method. The techniques for decoupling the circuit and implementing the parallel algorithm are described. The method is demonstrated in an electrical circuit simulation. Comparison of the computing time with the sequential approach confirms the computing efficiency of the proposed method.

Simulation Of Rail Voltage And Earth CurrentIn A PC-based Traction Power Simulator

Abstract: Electrical circuit simulation by setting up nodal voltage equations and inverting a conductance matrix is a powerful CAE tool. Running large models on PCs, however, requires economic computing and storage requirements. This paper describes an algorithm for compacting intermediate storage necessary for solving circuit models with a large, sparse conductance matrix. The algorithm is based on targeted directed elimination followed by Gaussian elimination with back substitution. An example is given of an electrical calculation in a timestepping railway traction simulator. The circuit represents a double-track light rail system with one branch. Outputs are given for train voltage, substation busbar feeding conditions and rail voltage, the latter also giving information about earth current.

Synthetic Testing of High Power A.C. Electrical Circuit Breakers

Abstract: 1,186,435. Testing circuit breakers. ASSOCIATED ELECTRICAL INDUSTRIES Ltd., ENGLISH ELECTRIC CO. Ltd., and A. REYROLLE & CO. Ltd. Jan. 31, 1968 [Feb. 20, 1967], No.8068/67. Heading G1U. A circuit breaker is tested over a make-break cycle in a system which simulates the sequence of normal duty voltage, short circuit current, transient recovery voltage and steady A.C. recovery voltage which would be encountered. The breaker S2 is connected to a first source circuit V which simulates the normal duty voltage and recovery voltage throughout the test. A switch S1 is automatically closed to connect the breaker to a second source circuit I simulating a short circuit current in response to a current flow, detected at D which takes place when the circuit breaker is closed to draw current from the first source. An oscillatory circuit including a pre-changeable capacitance C1 is operated to apply across the circuit breaker, when this is subsequently opened, a voltage simulating a transient recovery voltage. The steady voltage and current are derived from generators via chokes LR2, LR1 respectively and transformers T2 and T1. The steady voltage is applied to the test breaker S2 via a resistor R (for phase matching) and inductance-capacitance network TL for simulating the network between the supply and the breaker. The detector D may be a trigger plasma jet or laser beam source which, when current flow through the test breaker occurs on closure, initiates the closure of the breaker S1 so that the rated short circuit current is immediately applied. Breaker S3 is then closed and the breakers S2 (under test) and S1 are opened, at which time spark gap SP is triggered to connect across the test breaker the oscillatory circuit includes capacitor C1 and inductance L, to provide a waveform which simulates the transient recovery voltage, C1 being initially charged. A damping circuit L3 R3 is connected across the oscillatory circuit , while a rate control circuit C 2 R 2 is connected across the breaker to prevent spurious oscillations appearing on the injected current. The breaker S3 is subsequently opened so that only the steady recovery voltage V is finally applied across the breaker or alternatively the components L3, R3 may prevent C1 from resonating with T2.

Electrical systems for road vehicles

Abstract: In an electrical system for a road vehicle, a manually operable switch controls one electrical circuit of a vehicle. The switch has a metallic part associated with it, and this metallic part acts as the sensing element of a proximity switch which controls another electrical circuit of the road vehicle. One circuit may be the windshield wiper circuit, and the other the windshield washer circuit.

Generalised Variable-time-step TLMTechnique For Electrical Circuit Analysis

Abstract: This paper describes a generalised variable time step technique (VTS) for the Transmission-line Modelling (TLM) method. The method is applied to electrical circuit analysis with emphasis on circuits which have widely separately time constants. The generalised technique enables easy handling of both the transient and steady-state behaviour of electrical circuits and allows a substantial reduction in the simulation time. The generalised VTS TLM algorithm can be applied to all TLM stubs and forms the basis for future auto-timestepping TLM methods for circuit simulation.

Electrical demand priority circuit

Abstract: A circuit for controlling the provision of electrical energy to an accessory circuit in accordance with an established priority and the energy demands placed upon the remainder of the system by the other accessories powered therefrom is disclosed herein. The circuit includes a control transistor which provides an electrical interconnection between the vehicle bus bar and the accessory and its accessory battery. When the demands placed upon the remainder of the electrical circuit are high the control transistor limits or terminates the flow of energy to the high demand accessory portion of the circuit.