Eaton Power Xpert PXM 4000, Руководство пользователя и инструкция по установке

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12 Glossary
THD (Total Harmonic Distortion)
The rms value of the ac signal after the fundamental compo-
nent is removed and inter-harmonic components are ignored.
Expressed as a precent, it is the ratio of the harmonic distor-
tion to the rms value of the fundamental.
THD =%THD = X 100
Trigger
To cause a device to change state or to perform some other
operation. A signal that causes a circuit or device to change
state.
VA, VB, VC
Phase voltages for phases a, b and c respectively.
VAB, VBC, VCA
Line-to-line voltage between phase a & b, phase b & c, phase
c & a respectively.
VT (Voltage Terminals)
An instrument transformer designed for use in the measure-
ment or control of voltage. Its primary winding is connected
across the supply circuit.
Waveform Data
The numeric oscillographic values that may be captured. A
manifestation or representation or visualization of a wave,
pulse or transition (graph, plot, equation(s), table of coordi-
nate or statistical data).
NOTE: Some of the information provided within these defini -
tions have been extracted from The Authoritative Dictionary of
IEEE Standard Terms Seventh Edition.
THD
C
1
(
Σ
)
85
Cn
2
n=2
1/2