Formula variables
- hp is motor horsepower.
- V is line-to-line voltage.
- Efficiency is entered as a percent and converted to decimal form.
- PF is motor power factor.
Assumptions
- The estimate uses balanced three-phase motor current arithmetic.
- Voltage should match the actual motor nameplate or utilization voltage.
- Efficiency and power factor are editable because motor type and loading change the current estimate.
- This calculator does not replace motor nameplate FLA, overload selection, conductor sizing, branch-circuit protection, starter sizing, or installation approval.
Examples
10 hp at 600 V. A 10 hp motor at 600 V, 88 percent efficiency, and 0.85 PF estimates about 9.6 A.
Nameplate workflow. Use nameplate FLA whenever available; the calculator is a planning screen before equipment data is confirmed.