Electrical calculators

Cable sizing, voltage drop, three-phase power, motor starting, short-circuit current and generator load, for electricians and marine electrical officers.

• Battery capacity and runtimeRuntime of a battery bank under a constant load with Peukert correction, or the capacity for a target runtime; C-rate, usable energy, recharge Ah and time.
• Cable short-circuit withstandAdiabatic short-circuit check of a cable and its protective conductor, with the earth-fault loop impedance, fault current and disconnection time.
• Cable sizing and voltage dropVoltage drop, power loss and the minimum IEC conductor size for DC, single-phase and three-phase circuits from current, length, material and allowed drop.
• Generator load sharing with droopActive load sharing and bus frequency of paralleled generating sets with speed droop, with an optional isochronous set taking the balance.
• Generator load, kVA and fuelLoad factor, kVA, current and N−1 redundancy of parallel diesel generators, the recommended number of sets for a load band, and fuel, cost and CO₂ from SFOC.
• Lighting design (lumen method)Number of luminaires for a target illuminance from room index, utilisation and maintenance factors; power density.
• Motor starting current and voltage dipStarting current and kVA by method (DOL, star-delta, autotransformer, soft starter, VFD), voltage dip on a generator or network, torque at reduced voltage.
• Power factor correctionCapacitor kvar and capacitance to raise the power factor, released kVA and current, loss saving, resonance with the supply and detuning.
• Short-circuit current (IEC 60909)Three-phase short-circuit current at a switchboard from source, transformer and cable impedances; peak current and breaker check.
• Solar PV array and storage sizingArray size from daily load, peak sun hours and system losses; battery storage for days of autonomy; charge controller current.
• Three-phase power and motor currentkW, kVA, kvar and line current for three-phase, single-phase and DC circuits; motor full-load and starting current from the nameplate; power-factor correction.
• Transformer sizing and voltage regulationkVA from load and power factor with growth, rated currents, impedance voltage, voltage regulation and losses.