Basic Measuring Instruments

Jamie Nicholson

Alexander McEachern

Scott C Terry

Erich W Gunther

Craig S Waterman

An apparatus and method for characterizing an alternating current power line which uses a library of waveforms and associated spectra of digitally sampled alternating current power system voltage or current waveforms. The library of waveforms is built as new waveforms are measured from the alternating current power line. A measured waveform that is not found in the library will be converted to frequency-domain representation, using a Discrete Fourier Transform, that will then be stored in the library. When the library becomes full, the frequency domain representation of the new waveform will be stored in place of the least used waveform currently stored in the library.

Waveform library for characterizing an AC power line spectrum

A stand-alone electronic measuring instrument for measuring AC (alternate current) power parameters on a utility distribution system wherein the measurement results are communicated telephonically to a facsimile device. Well-known techniques are used to acquire and accumulate analog signals representative of voltages and currents on an AC power system and digital signals. If the signals exceed a programmed threshold, or if an interval of time elapses, or if some other triggering even occurs, the instrument prepares a bit-mapped digital report on its accumulated input signals which may contain text, graphics, or both. The instrument then employs well-known techniques to telephonically transmit this report directly to a facsimile receiver without employing an intervening computer system.

Electronic remote data recorder with facsimile output for utility AC

An instrument for measuring voltage harmonics and current harmonics on AC (alternating current) power systems. The instrument includes the ability to determine when threshold limits have been exceeded for harmonics. The instrument also includes timing thresholds whose inputs are activated when the harmonic thresholds are exceeded. A single harmonic threshold is applied to measurements from multiple phases on poly-phase systems by comparing the square rot of the sum of the squares of measurements from each phase to the harmonic threshold. Three indicators show when voltage harmonic limits are exceeded, current harmonics limits are exceeded, or both voltage and current harmonic limits are exceeded simultaneously.

Harmonic measuring instrument for AC power systems with a time-based

An instrument for measuring voltage harmonics and current harmonics on AC (alternating current) power systems. The instrument includes the ability to determine when threshold limits have been exceeded for harmonics. The instrument also includes timing thresholds whose inputs are activated when the harmonic thresholds are exceeded. A single harmonic threshold is applied to measurements from multiple phases on poly-phase systems by comparing the square root of the sum of the squares of measurements from each phase to the harmonic threshold. Three indicators show when voltage harmonic limits are exceeded, current harmonics limits are exceeded, or both voltage and current harmonic limits are exceeded simultaneously.

Harmonic measuring instrument for AC power systems with latched

An instrument for measuring voltage harmonics and current harmonics on AC (alternating current) power systems The instrument includes the ability to determine when threshold limits have been exceeded for harmonics. The instrument also includes timing thresholds whose inputs are activated when the harmonic thresholds are exceeded A single harmonic threshold is applied to measurements from multiple phases on poly-phase systems by comparing the square root of the sum of the squares of measurements from each phase to the harmonic threshold. Three indicators show when voltage harmonic limits are exceeded, current harmonics limits are exceeded, or both voltage and current harmonic limits are exceeded simultaneously.

Harmonic measuring instrument for AC power systems with poly-phase

A locking apparatus is coupled to and incorporated within an electronic instrument to ensure that the instrument operates within a predetermined set of performance parameters. The instrument's operating characteristics will be tested and measured by an external, automatic test system as is typical in the manufacture of many electronic instruments. The locking device will prevent the ordinary operation of the instrument until the instrument has successfully passed the tests administered by the automatic test system. Upon successful completion of the tests, the test system will communicate a signal to the locking device. Upon receipt of the control signal, the locking device will 'unlock' the instrument allowing normal operation. In order to ensure that routine calibration takes place, the locking device can be instructed to periodically disable normal operation of the instrument until another performance test is administered by an automatic test system.

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Foster City, CA, United States of America

Jamie Nicholson