Technical toolbox

Electrical calculators.

Choose a tool, check the units and assumptions, and compare the result with the worked example.

Estimate luminaire count, average maintained illuminance, connected load and energy use with the lumen method.

Use power, quantity and operating time to estimate kWh consumption and cost at your own unit price.

Calculate current and dissipated power from voltage and resistance for a DC or purely resistive circuit.

Calculate current from electrical active input power, voltage and power factor in a single-phase or balanced three-phase system.

Estimate active input power from current, voltage and power factor.

Estimate full-load current from shaft output power, line voltage, efficiency and power factor.

Estimate single-phase motor current from shaft power, voltage, efficiency and power factor.

Convert mechanical horsepower to kilowatts.

Convert kilowatts to mechanical horsepower.

Estimate resistive cable voltage drop from current, length, conductor area and resistivity.

Estimate conductor area required by a chosen voltage-drop target.

Find the ratio of active power in kW to apparent power in kVA.

Estimate capacitor reactive power for improving an inductive load’s power factor.

Apply temperature and grouping factors to a manufacturer’s base current rating.

Apply a chosen current factor and show the next listed nominal rating.