摘要:
A light driven remote system and power supply therefor that includes a laser diode that provides pulses of light to a fiber optic cable. The pulses of light are detected by a remote photodiode that is connected in parallel with a step-up transformer. The output of the step-up transformer is filtered to provide power for a remote system. Data transmission from the remote system is synchronized with transmission of light to the photodiode.
摘要:
An AC electric energy meter is coupled to a source of AC electrical energy and to an AC load. A sensing circuit senses the amount of AC electric energy consumed by the AC electric load. An AC electric energy measuring circuit generates a pulse signal representative of the amount of AC electric energy consumed by the AC electric load. A switching circuit receives the pulse signal from the AC electrical energy measuring circuit and controls current flow from the AC electrical energy source to a stepper motor to drive an output shaft of the stepper motor in a unidirectional manner based on the pulse signal. A register is coupled to the output shaft of the stepper motor for registering the amount of electrical energy consumed by the AC electric load based on the amount of rotation of the output shaft of the stepper motor. The stepper motor includes a core having an air gap, a rotatable permanent magnet positioned in the air gap and a winding wound about the core, for generating a magnetic field across the air gap. The switching circuit controls the direction of current flow through the winding to alternately reverse the polarity of the magnetic field across the air gap, so that the permanent magnet rotates in a unidirectional manner.
摘要:
An electrical motor contactor or controller is taught in which control signals from remotely located pushbuttons are supplied to the logic portion of the controller for the purpose of initiating or stopping a predetermined contactor or controller actions. The controller or contactor is of a universal nature adapted for the acceptance of relatively high voltage AC control signals or relatively low voltage DC control levels. For instance, a 120-volt AC signal may be provided or a 5-volt DC level may be provided. Because an AC signal may be provided to the controller, capacitive filter elements are utilized in the control circuit for filtering transients or AC components above a predetermined frequency which may be 60 Hz for example. Furthermore, voltage regulator elements within the control circuit and the microprocessor input terminals within the control circuit represent relatively high impedance in the discharge path for the aforementioned capacitors. Furthermore, regardless of whether DC control signals or AC control signals are supplied to the control circuit, all values are converted to relatively low level DC values for utilization as inputs by the microprocessor. In those circumstances in which an AC control signal is utilized interruption of the AC control signal, such as may occur when a closed pushbutton is opened, alerts the microprocessor that a change in control state has taken place. The capacitive elements which are used as filters may retain a charge thereacross for a significant portion of time because of the presence of the high impedance discharge paths. Therefore, the microprocessor in reading the control line may mistake the residual voltage on the charged capacitor for a positive indication of a control signal. In order to avoid this, it is necessary to periodically in a controlled manner attempt to discharge the capacitive elements so that subsequent readings will not give a false indication. In order to do this, the input terminals of the microprocessor are periodically provided with digital logical zero value which represents a near short circuit condition for the capacitors thus, discharging the capacitive elements.
摘要:
Programmed overcurrent protection control apparatus with selectable time-overcurrent operation to govern the interruption of current through at least one power line associated with either a ground phase or a power phase of a power system network is disclosed. A programmed processor is included to derive an overcurrent time-to-trip in accordance with sampled measurement current values of the power line and selected derivation constants stored in a memory look-up table. The derivation constants are selected from the look-up table based on derivation parameters which may be set and read by the programmed processor from time to time. The programmed processor utilizes the selected derivation constants to derive the time-to-trip over a number of predetermined time intervals during which the overcurrent condition persists. An alternate overcurrent time-to-trip relationship utilizing different derivation parameters selected from the look-up table may be utilized for the conditions in which overcurrent exists in an initial predetermined range. In some situations, both of the derivation relationships may be used concurrently to derive the overcurrent time-to-trip.
摘要:
A supervisory circuit for use in an integrated circuit to supervise the program execution of a processing unit is disclosed. The processing unit generates a restart signal at a particular duty cycle under proper program execution conditions and at an undesirable duty cycle under improper program execution conditions. The supervising circuit includes a capacitive or like circuit element for converting the restart signal into a signal representative of the duty cycle thereof and compares the generated signal to a reference window comprising upper and lower reference values. Should the generated signal exceed the boundaries of the window reference, a corresponding control signal is generated to change the circuit conditions and generate a reset signal to the processing unit to govern the program execution thereof to a prespecified point from which point program execution may continue upon removal of the reset signal.
摘要:
Starting and operating method and apparatus for discharge lamps comprises a current-limiting and rectifying means which provides at its output a low-ripple current-limited direct current. To effect lamp starting, a series-connected inductor and capacitor form a high "Q" resonant circuit with the capacitor connected across the lamp to be operated. This starting circuit connects through a blocking capacitor and charging resistor across the low-ripple source of DC. A pair of transistors which comprise an oscillator are connected emitter-to-collector across the source of DC, with the common-connected emitter and collector connected to the blocking capacitor. A drive air-core transformer has separate feedback windings in the starting and operating circuits and drive windings are associated with the transistors. A trigger diode is used to initially pulse one of the transistors which initially oscillate to generate square waves having a frequency corresponding to the resonant frequency of the starting circuit. After the lamp strikes, the transistors operate in a self-oscillating mode with the operating frequency determined by the rate of current flow into the operating feedback winding.
摘要:
Add-on device for lead-type ballast comprises additional inductor and series-connected controlled AC switching means which are connected in parallel circuit with the capacitor portion of the lead-type ballast such as is used to operate an HID sodium lamp. The add-on device has a sensing and control circuit which operates to sense a lamp operating parameter in order to control the actuation of the AC switching means which in turn controls in predetermined fashion the operation of the ballasted lamp. The inductor and AC switch and sensing and control means of the add-on device are all packaged within a can-shaped member which has dimensions similar to those of the conventional capacitor can for the lead-type ballast. All the elements of the add-on device are potted within the capacitor can with terminal means extending from an end portion thereof for ready connection along with an exposed potentiometer portion to enable the control to be adjusted. The usual luminaire which utilizes a lead-type ballast normally incorporates one capacitor, although most luminaires are provided with the space for an additional capacitor, even though it is not needed. The present packaged add-on device readily fits into their available but unused space so that it is readily incorporated into existing luminaire designs.
摘要:
A circuit interrupter includes a digital trip unit containing a microprocessor. The circuit interrupter also includes current transformers for sensing current flow through the contacts of the interrupter and for providing operating power to the trip unit. The current transformers monitoring current flow through the breaker and control potentiometers receiving operator-entered values of the product of line voltage and power factor are connected to the microprocessor to supply it with the values needed to compute real power flow through the interrupter and to display the numeric value of this power flow. The power flow is compared to an operator-entered limit value of peak demand power, and an alarm signal is generated whenever power flow exceeds the limit value peak demand. Integration capability is also provided to calculate energy flow through the contacts in megawatt hours and to present the numeric value of this energy flow.
摘要:
A circuit interrupter includes a microprocessor-based trip unit, a numeric display, and a plurality of potentiometers each associated with one parameter of the time-current trip characteristic of the circuit interrupter. The trip unit provides a sequential display of the present setting values of the time-current trip characteristic parameters. Adjustment of any of the potentiometers is operable to interrupt the sequential display and to cause the present setting of the parameter associated with the adjusted potentiometer to be displayed. Adjustment of the potentiometer to either limit of its travel causes the most conservative setting value for that parameter to be selected. A hysteresis feature is provided to require a significant adjustment of the potentiometer before a different parameter setting will be selected.Although the potentiometers are continuously variable, operator adjustment thereof results in the selection of one of eight predetermined discrete values stored in the trip unit.
摘要:
An energy-conserving solid-state-controlled illumination system which operates high-intensity-discharge lamps. The system operates the lamps at about a predetermined rated power consumption with a relatively high light output for a predetermined initial period of time during the initial night when a high degree of illumination is most needed. The system then operates the lamps for a later period of the night at a reduced power for a second predetermined period of time when a lower degree of illumination can be tolerated. Then if the lamps are still energized according to seasonal variations, the system thereafter operates the lamps at the relatively high light output for the remainder of the night to accommodate early morning traffic.