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3-Phase RMS Meter
Root-mean-square meter for a three-phase scalar signal triple (A, B, C). Computes out = sqrt(mean((a² + b² + c²) / 3)) over a sliding 1/frequency window. For a BALANCED three-phase sinusoid at the configured frequency this equals the per-phase RMS amplitude (A_pk / √2) at every instant once the window has filled — e.g. wire the three phase voltages of a 480 V (LL) / 277 V (LN) source in and the output settles at 277. For UNBALANCED or harmonic-laden inputs the window smooths the per-step variation and the result is the RMS of the equivalent symmetric magnitude.
Category: Continuous
Keywords: RMS, root mean square, rms meter, true rms, three phase, 3-phase, 3 ph, 3ph, three-phase, phase, ph, meter, magnitude, AC, amplitude, voltmeter, ammeter, abc
Ports
| Name | Direction | Value type | Notes |
|---|---|---|---|
in_a | input | double | |
in_b | input | double | |
in_c | input | double | |
out | output | double |
Parameters
| Name | Label | Type | Default | Units | Description |
|---|---|---|---|---|---|
frequency | f (Hz) | double | 60 | — | Fundamental frequency used to size the averaging window (window = 1 / frequency). For BALANCED three-phase sinusoidal inputs the window is technically unnecessary — (a² + b² + c²) / 3 is already constant in time — but a finite window is needed to suppress per-step variation on unbalanced or distorted inputs. Set to your AC system's nominal frequency (60 in North America, 50 in Europe). |
Implemented in C++ class SimCompCtlRms3ph (components/control/CSim_comp_ctl_rms_3ph/sim_comp_ctl_rms_3ph.h).