Digital ac monitor

Patent · Tue Jun 09 04:00:00 EDT 1987

OSTI ID:7255125

Hart, G W; Kern, Jr, E C

An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer. 24 figs.

• DOE Contract Number: AC02-76ET20279
• Assignee: Massachusetts Inst. of Tech., Cambridge, MA (United States)
• Patent Number(s): US 4672555; A
• Application Number: PPN: US 6-662392
• OSTI ID: 7255125
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426000* -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
ALTERNATING CURRENT
ANALOG-TO-DIGITAL CONVERTERS
COMPUTER CALCULATIONS
CURRENTS
DATA PROCESSING
ELECTRIC CURRENTS
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
MONITORING
PROCESSING