© 2008 Siemens Energy & Automation, Inc. All Rights Reserved
ACCESS 9340 and 9360 Meters PMCM-9340D-0208
Appendix D—Glossary 2/2008
EN–242
line-to-neutral voltages—measurement of the rms line-to-neutral voltages of the
circuit.
maximum demand current—highest demand current measured in amperes since the
last reset of demand.
maximum demand real power—highest demand real power measured since the last
rest of demand.
maximum demand voltage—highest demand voltage measured since the last reset of
demand voltage.
maximum demand (peak demand) —highest average load during a specific time
interval.
maximum value—highest value recorded of the instantaneous quantity such as Phase
A Current, Phase A Voltage, etc., since the last reset of the minimums and maximums.
minimum value—lowest value recorded of the instantaneous quantity such as Phase
A Current, Phase A Voltage, etc., since the last reset of the minimums and maximums.
nominal—typical or average.
parity—refers to binary numbers sent over the communications link. An extra bit is
added so that the number of ones in the binary number is either even or odd, depending
on your configuration). Used to detect errors in the transmission of data.
partial interval demand—calculation of energy thus far in a present interval. Equal to
energy accumulated thus far in the interval divided by the length of the complete
interval.
phase currents (rms)—measurement in amperes of the rms current for each of the
three phases of the circuit. See also maximum value.
phase rotation—phase rotations refers to the order in which the instantaneous values
of the voltages or currents of the system reach their maximum positive values. Two
phase rotations are possible: A-B-C or A-C-B.
potential transformer (PT)—also known as a voltage transformer
power factor (PF)—true power factor is the ratio of real power to apparent power using
the complete harmonic content of real and apparent power. Calculated by dividing watts
by volt amperes. Power factor is the difference between the total power your utility
delivers and the portion of total power that does useful work. Power factor is the degree
to which voltage and current to a load are out of phase.
real power—calculation of the real power (3-phase total and per-phase real power
calculated) to obtain kilowatts.
rms—root mean square. Meters are true rms sensing devices.
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