Three-Phase Electrical Calculator

Power & Load

Active, reactive and apparent power and line current.

Voltage Drop

Voltage drop along a three-phase cable.

Cable Sizing

Select cross-section by current and voltage drop.

Power Factor Correction

Capacitor rating to raise the power factor.

Short-Circuit Current

Symmetrical short-circuit current.

Motor Current

Full-load and starting current.

Transformer Rating

Primary and secondary currents.

Symmetrical Components

Decompose unbalanced quantities into sequence components.

Harmonic Distortion

Total harmonic distortion and IEEE 519 limits.

Load List & Single-Line

Collect loads and draw the single-line diagram.

Motor Protection

Overload and short-circuit settings for motors.

Parallel Transformers

Load sharing and parallel checks for two transformers.

Voltage Dip & Power Quality

Voltage sag magnitude and duration from a fault or a load step.

DC Panel Battery Sizing

Battery capacity and charger setpoints for a DC panel.

EN 50160 Power Quality

Voltage, frequency, harmonics, unbalance and dip-frequency compliance.

Protection Selectivity

Upstream/downstream relay grading and margin.

Short-Circuit Stability

I²t thermal duty and peak withstand check.

Earthing & RCD

Earth-fault protection for TN, TT and IT systems.

Capacitor Resonance

Parallel-resonance frequency and harmonic proximity.

Motor Starting

DOL / Y-Δ / soft-start / VFD comparison.

PV / Storage Quality

Harmonics, DC injection and flicker at the PCC.

Arc-Flash Energy

Incident energy and arc-flash boundary (IEEE 1584).

Capacitor Inrush

Peak inrush and reclose interval of shunt banks.

Cable Thermal

Short-circuit section check k²S² ≥ I²t.

Earthing

Electrode resistance and touch / step voltage.

Motor Protection

Overload, locked-rotor, unbalance and ground settings.

Harmonic Filter

Tune an L–C single-tuned branch to a harmonic.

UPS Battery

String sizing and backup runtime from Ah.

Transformer Differential

Restraint setting, balance and inrush block.

Contactor (DOL)

AC-3 make/break capacity and selection.

DC Short-Circuit

Steady I, peak and I²t of a DC fault.

LV Selectivity

Main vs branch breaker grading and I²t.

CT Saturation

10% error knee-point and ALF check.

UPS Paralleling

Circulating current and load share.

Arc-Suppression Coil

Petersen-coil tuning and residual current.

Motor Restart / UV Trip

Undervoltage release and re-acceleration.

Neutral Resistor Ground

NER current, earth-fault and trip setting.

Locked-Rotor Restart

Staggered motor re-acceleration batching.

Zero-Seq Directional

Transformer 3I0 overcurrent + direction.

Distance Protection

Line Zone 1/2/3 reach and relay impedance.

Inverse-Time Overcurrent

IEC 60255-151 NI/VI/EI/LTI curve setting.

Current 3-Stage

Non-directional overcurrent I/II/III grading.