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Motor Sizing & Electrical Specification | Engineering Database

Motor Sizing & Electrical Specification

electrical

Looks up motor full-load current (NEC 430), efficiency, power factor, torque characteristics, and starting current for a given motor HP and voltage. Returns FLC at all standard voltages, locked-rotor current, and NEMA performance data.

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Hp*

Motor rated horsepower. Standard NEMA sizes: 0.5, 0.75, 1, 1.5, 2, 3, 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200, 250, 300, 350, 400, 450, 500. Fractional HP (1/6, 1/4, 1/3) available for single-phase only. Typical: 0.5-10 hp HVAC, 10-200 hp pumps/compressors, 200-5000 hp large industrial.

Phases

Number of electrical phases. 1-phase for small motors up to ~10 HP (residential, light commercial). 3-phase for industrial applications and motors above 1 HP. If omitted, defaults to 3-phase.

Voltage

System voltage for FLC lookup. Standard NEC voltages: 115, 200, 208, 230, 460, 575 V. Non-standard voltages are interpolated. Typical: 460V for industrial 3-phase, 230V for commercial, 115V for small single-phase. If omitted, defaults to 460V.

Motor Class

Motor efficiency class for performance data lookup. Options include NEMA_PREMIUM_3PH (IE3 equivalent), NEMA_STANDARD_3PH, etc. Determines efficiency, power factor, and torque characteristics returned. If omitted, defaults to NEMA_PREMIUM_3PH.

Load Percent

Actual operating load as a percentage of rated HP. Used to interpolate efficiency and power factor at the operating point. Motors are most efficient near 75-100% load; below 50% efficiency drops significantly. If omitted, defaults to 100% (full load).

Reference data

This calculator pulls live values from the following engineering reference tables in the database.

motor flc
motor efficiency

About this calculator

Motor Sizing & Electrical Specification is part of the Engineering Database calculator suite. Each tool runs deterministic calculations against authoritative reference data and code-compliant methods, so results are reproducible and traceable to source standards.

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