Digital ac monitor

Patent · Tue Jun 09 00:00:00 EDT 1987

OSTI ID:866275

Hart, George W ^[1]

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1. Natick, MA

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.

• Research Organization: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• DOE Contract Number: AC02-76ET20279
• Assignee: Massachusetts Institute of Technology (Cambridge, MA)
• Patent Number(s): US 4672555
• Application Number: 06/662,392
• OSTI ID: 866275
• Country of Publication: United States
• Language: English

Related Subjects

digital
monitor
apparatus
method
provided
monitoring
plurality
analog
circuits
sampling
voltage
current
waveform
circuit
predetermined
intervals
converting
samples
format
storing
digitized
stored
calculate
variety
electrical
parameters
derived
non-derived
quantities
repeatedly
calculated
separate
cycles
averaged
averaging
period
produces
accurate
reading
especially
power
varies
wide
dynamic
range
frequency
measured
timing
upward
zero
crossover
starting
timer
voltage waveform
dynamic range
electrical parameter
wide dynamic
digital form
electrical parameters
predetermined interval
/700/324/702/