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63230-300-212 Glossary
April 2001
195
© 2001 Schneider Electric All Rights Reserved
rms—root mean square. Circuit monitors are true
rms sensing devices. See also
harmonics (rms
).
sag/swell—fluctuation (decreasing or
increasing) in voltage or current in the electrical
system being monitored. See also,
voltage sag
and
voltage swell
.
scale factor—multipliers that the circuit monitor
uses to make values fit into the register where
information is stored.
SMS—see System Manager Software.
synchronized demand—demand intervals in
the circuit monitor that can be synchronized with
another device using an external pulse, a
command sent over communications, or the
circuit monitor’s internal real-time clock.
System Manager Software (
SMS)—software
designed by POWERLOGIC for use in evaluating
power monitoring and control data.
system type—a unique code assigned to each
type of system wiring configuration of the circuit
monitor.
thermal demand—demand calculation based on
thermal response.
TIF/IT—telephone influence factor used to
assess the interference of power distribution
circuits with audio communications circuits.
Total Harmonic Distortion (THD or thd)—
indicates the degree to which the voltage or
current signal is distorted in a circuit.
total power factor—
see power factor
.
transient—sudden change in the steady-state
condition of voltage or current.
troubleshooting—evaluating and attempting to
correct problems with the circuit monitor’s
operation.
true power factor—see
power factor
.
undervoltage—decrease in effective voltage to
less than 90% for longer than one minute.
VAR—volt ampere reactive.
VFD—vacuum fluorescent display.
voltage interruption—complete loss of power
where no voltage remains in the circuit.
voltage sag—a brief decrease in effective
voltage lasting more than one minute.
voltage swell—increase in effective voltage for
up to one minute in duration.
voltage transformer (VT)—see
potential
transformer
.
voltage unbalance—percentage difference
between each phase voltage with respect to the
average of all phase voltages.
waveform capture—can be done for all current
and voltage channels in the circuit monitor.