This simulator models a three-phase RLC load bank that can be wired as a wye (star, four-wire) or delta connection off the same source, so you can hold the supply constant and see exactly what the connection itself changes — and where the √3 factor between line and phase quantities actually comes from.
• A real-time 3D wiring board (01 Connection lab) with an isometric view, wiring view and auto-orbit camera, an expand view, clickable components with callouts, and moving current-direction markers slowed to 0.25 cycle/s. • Load-connection selector (wye/star or delta), a load-neutral-to-source-N toggle, energize/open contactor controls, run-time/step (0.1 s)/advance 1 s/advance 30 s time controls, a reset-trip button, per-branch impedance controls (R and X₅₀ for each of 3 branches) with a "copy branch 1 → all" button, a fault-fixture selector (open neutral, high-resistance neutral, open line A, open branch 1, low-impedance branch 1, source phase B sag) and an overcurrent-protection toggle. • 02 Phasors & waveforms: voltage-vector and current-vector phasor plots (switchable between branch/line/source voltages and line/branch currents), a waveform chart (branch voltage, line current or instantaneous branch/total power) over two electrical cycles, a power-accounting panel and a two-wattmeter method readout. • 03 Wye vs. delta: a comparison mode (same branch impedances, or equivalent balanced loads with ZΔ = 3 ZY), a break-before-make star–delta reconnection demonstration (Y for 3 s → open 0.3 s → Δ), and a current-vs-resistance sweep chart comparing wye and delta line current. • 04 Experiments & diagnostics: a 24-check verification bench, a troubleshooting challenge with a mystery fault to diagnose, and a timestamped event log with JSON export. • 05 Learn & quiz: guided lessons, a model-scope statement with references, and a knowledge-check quiz. • A virtual true-RMS meter with selectable red/black probes, a clamp-current selector (each line, neutral or each branch), conductor/protection settings, and a "Start guided investigation" tour button.
In a balanced wye connection, each branch sees the source's phase voltage directly, but the line-to-line voltage is √3 times larger because it's the vector difference between two 120°-apart phase voltages, not a simple sum. Line current equals branch current, since each line feeds only one branch in series.
In a balanced delta connection, each branch is connected directly across a line-to-line voltage, so branch voltage equals line voltage. But each line now supplies two branches simultaneously, so line current is the vector sum of two branch currents 120° apart, which works out to √3 times the branch current. The simulator's comparison mode lets you hold branch impedance constant and switch connections, so you can watch these relationships play out in the live phasors and meter readings rather than just the formulas.
The fault fixtures reveal connection-specific behavior: an open neutral only matters in a wye system with unbalanced branches, since it lets the star point float and unbalances the branch voltages — the lab notes explicitly that neutral-only faults have no electrical effect on a delta load, which has no neutral at all. Source phase sag and open-line faults affect both connections, but differently, since delta redistributes current across two branches per line while wye isolates each line to one branch.
The virtual true-RMS meter and clamp ammeter let you probe any two points or any conductor directly, and the two-wattmeter method panel demonstrates how W₁ + W₂ measures total three-wire real power even under unbalance. The 24-check verification bench runs isolated fixtures to confirm the underlying vector/Kirchhoff/power solver is correct without touching your live circuit, and the troubleshooting challenge tests whether you can diagnose a fault from meter and phasor readings alone. This is a passive-load teaching model — no harmonics, transformer vector groups, high-leg delta, grounding faults, motor dynamics or electromagnetic transients are simulated.
In a wye (star) connection, one end of each branch load is tied to a common neutral point, and each branch sees the source's phase voltage. In a delta connection, branches are connected end-to-end in a triangle across the line-to-line voltages directly, with no neutral point. The same source and the same branch impedances give different voltage and current relationships depending on which connection you choose.
For a balanced wye load, line-to-line voltage is √3 times branch (phase) voltage because it is the vector difference of two phase voltages 120° apart, and line current equals branch current. For a balanced delta load, branch voltage equals line voltage, but line current is √3 times branch current because each line feeds two branches whose currents combine vectorially at 120° apart.
A wye load's neutral point only stays at zero potential if the three branches are balanced; if they are not, an open neutral lets the star point float and unbalances the branch voltages, which the simulator's "open neutral conductor" fault fixture demonstrates directly. A delta load has no neutral conductor at all, so neutral-only faults have no electrical effect on it.
The Experiments & diagnostics tab includes a bench that runs 24 automated checks against the underlying vector math, Kirchhoff's-law and power-accounting solver on isolated test fixtures, without altering your live circuit — confirming the phasor calculations, two-wattmeter power method and fault behavior are computed correctly before you rely on them to interpret your own experiments.