HP ad Ampere Calcolatrice
Inserisci la potenza in HP e l'efficienza del tuo motore per trovare l'assorbimento di corrente richiesto. Essenziale per dimensionare avviatori, contattori e interruttori di protezione.
Analisi del Carico del Motore
HP Meccanico → Corrente Elettrica
Requisito di Amperaggio a Pieno Carico (FLA) per il tuo motore.
La Formula di Conversione
Un cavallo meccanico equivale esattamente a 746 watt — la base di tutte le conversioni da HP ad ampere.
Motori CC
I = (HP × 746) ÷ (V × Eff) L'efficienza (Eff) tiene conto delle perdite del motore — un motore efficiente al 90% assorbe più corrente di quanto suggerisca la sua potenza in HP.
Motori CA Monofase
I = (HP × 746) ÷ (V × Eff × PF) I motori CA richiedono il fattore di potenza oltre all'efficienza — entrambi riducono l'erogazione di potenza effettiva rispetto alla corrente in ingresso.
Motori CA Trifase
I = (HP × 746) ÷ (√3 × V × Eff × PF) I motori trifase distribuiscono la corrente su tre fasi — il fattore √3 (1,732) tiene conto della relazione di tensione linea-linea.
How to Convert Horsepower to Amps
Horsepower (HP) is a mechanical power rating used to describe motor output capacity. To find the electrical current (amps) a motor draws from the supply, you need to account for the mechanical-to-electrical conversion constant (746 W/HP), the motor's efficiency, and — for AC motors — the power factor. This calculation is essential for sizing motor starters, circuit breakers, cables, and variable frequency drives (VFDs).
Why 746 Watts Per Horsepower?
One mechanical horsepower is defined as exactly 550 foot-pounds per second, which converts to 745.7 watts. This constant is the universal bridge between mechanical and electrical motor ratings. Electric motors are rated in both HP (output) and kW (input), with the difference representing heat losses in the motor windings and core.
Motor Nameplate Data You'll Need
- HP Rating: The mechanical output power the motor is designed to deliver at full load.
- Voltage (V): The supply voltage the motor is designed for — often listed as dual voltage (e.g., 230/460V).
- Efficiency (η): Found on the nameplate as a percentage. Premium-efficiency motors typically run 90–96%.
- Power Factor (PF): Listed on the nameplate or in the datasheet. Induction motors typically have PF of 0.80–0.92 at full load.
- Full Load Amps (FLA): The nameplate should also list FLA directly — cross-check your calculated value against this number.
Step-by-Step Conversion
- Read the HP: Use the motor's rated output horsepower from the nameplate.
- Multiply by 746: Convert HP to watts (1 HP = 746W).
- Divide by Voltage: Include the √3 factor for three-phase line voltage.
- Apply Efficiency: Divide by motor efficiency as a decimal (e.g., 0.90 for 90%).
- Apply Power Factor (AC): Divide by PF for AC motors.
- Size Protection at 125%: NEC requires motor branch-circuit conductors rated at 125% of FLA for continuous operation.