Locked-Rotor kVA Calculator

How Locked-Rotor kVA works

The result comes from kVA = √3 × V × I ÷ 1000. Locked-Rotor kVA uses Line voltage, Locked-rotor current to report Locked-rotor kVA.

With the loaded values, locked-rotor kVA evaluates to 124.71 kVA. Keep other entries fixed when exploring a measurement range.

Inputs for Locked-Rotor kVA

Line voltage and Locked-rotor current belong to Locked-Rotor kVA. Keep source units with line voltage.

The opening values are placeholders for testing the arithmetic. Use Motor Capacitor Calculator as the follow-up for capacitive reactance target.

Line voltage

Example entry: 400 V.

Locked-rotor current

Example entry: 180 A.

Reading the Locked-Rotor kVA result

This output represents Locked-Rotor kVA. For estimated motor speed, use VFD Motor Speed Calculator.

Standard size, duty, temperature, and transient checks remain outside this single equation.

Measurement and units

Motor nameplate data, duty, enclosure, starting method, load profile, and thermal limits govern final selection. Check prefixes on line voltage.

Scenario differences are meaningful only with consistent units and observation points.

Limits of this calculation

Use line quantities for a three-phase motor.

This equation represents one relationship rather than a full circuit simulation. Unentered effects remain outside Locked-Rotor kVA. Compare this result with Motor Energy Consumption Calculator when motor energy is also needed.

A useful Locked-Rotor kVA comparison

Save the initial locked-rotor kVA before adjusting line voltage. A low and high case is more informative than adding an unexplained safety factor after the calculation. If the next question concerns motor efficiency, open Motor Efficiency Calculator.

Document the alternate line voltage source.

Questions about Locked-Rotor kVA