摘要:
In a typical power system, a motor bus is fed by a main power system; and, an auxiliary system is provided to alternatively feed the motor bus. When a fast transfer from the main power to the auxiliary power system is desired, for example, in case of fault occurring in the main system, the inventive method transfers power in a synchronous mode; that is, power is transferred from the auxiliary system to the motor bus when the phase difference of the auxiliary system with respect to the frequency of the residual voltage on the motor bus is essentially zero degrees.
摘要:
A synchronizing check relay is used in an electrical transmission network for controlling a circuit breaker to interconnect first and second transmission lines to establish power flow therebetween and includes an input circuit for receiving signals from first and second transmission lines. A phase difference generator generates a phase difference signal proportional to a phase difference between said signals from said first and second transmission lines. A phase difference comparator receives the phase difference signal and produces a phase output signal at a selected phase condition. An adjustable timer produces a timer signal after a selected time interval in response to the phase comparator to insure a proper phase difference between the transmission lines. The voltage sensor produces a breaker closing inhibit signal when one of the alternating current voltages is outside a reference limit. A control circuit is responsive to the phase output signal, the time signal and the breaker closing inhibit signal for providing a control response to the circuit breaker.
摘要:
Power transfer relay circuitry is disclosed for providing synchronous transfer of power such as from an auxiliary source or system to a motor or motor bus; the circuitry effects the transfer of power when the phase difference between the motor bus and the auxiliary power source is very nearly zero degrees.
摘要:
It is believed that Raytheon uses lightning strikes to prevent rotating clouds from building into hurricanes. In this invention, metal towers are placed on islands so as to safely ground the Raytheon man made lightning strokes without damage to property or loss of life.
摘要:
Under load tapchanging voltage regulators with source and load connections, series and shunt transformers, switching devices for causing selectable levels of electric power to flow in either direction between the series and shunt transformers, and tapchanger controls for sensing the voltage at said load connections and causing the switching devices to select proper electric power flows so as to maintain desired voltages at the load connections.
摘要:
An extremely low frequency (ELF) receiver that operates at the 6 Hz to 9 Hz range to synchronously receive signals from the electric (E) field or the magnetic (H) field of the earth's resonant (TS) frequency and other signals of interest.
摘要:
A process for sampling half cycles of AC waves and using precomputed stacks of sine values for obtaining fundamental components and odd harmonic phasers of said AC waves.
摘要:
A system and method of paralleling tapchanging transformers. The transformers are connected to provide a daisy chain of output load currents processed as pairs of currents by each tapchanger control. Transformer load currents are balanced as desired regardless of whether or not transformer primaries are supplied in parallel.
摘要:
A method for the control of wall thickness of an extruded thermoplastic material. The method includes extruding a thermoplastic material from an extruder through a die gap formed between first and second die lips. One of the die lips has a plurality of separate sectors adjacent the die gap, with each sector having a circulating oil passageway therein. The circulating oil passageways are connected in a series along the die gap. The method includes circulating through each circulating oil passage, within each sector adjacent the die lip, a heat transfer oil from a common source at a selected heating or cooling temperature. The method includes controlling the rate of flow of said heat transfer oil in each sector by an adjustable flow control valve, in order to control the temperature of each sector, and thereby to adjust the viscosity of the thermoplastic material being extruded, and controlling the wall thickness of the extruded thermoplastic material.