Estimate voltage, shaft power, current or motor efficiency for DC, single-phase AC or balanced three-phase AC, with explicit power-factor assumptions.
- All Unit Converters
- CC to HP Calculator
- WHP to HP Calculator
- HP to Amps Calculator
- HP to kVA Calculator
- RWKW to HP Calculator
- HP to Torque Calculator
- HP to Joules Calculator
HP To Voltage Formula
The following DC steady-state formula estimates voltage from mechanical shaft horsepower, current and motor efficiency. For single-phase AC, include power factor in the denominator; for balanced three-phase AC, also include โ3 and use RMS line-to-line voltage and line current.
Variables:
- V is the voltage in volts
- HP is mechanical shaft horsepower; 1 hp = 745.6998715822702 W (metric PS is different)
- I is the current in amperes
- ฮท is motor efficiency as a decimal between 0 and 1; enter a percentage in the calculator
For DC, multiply mechanical horsepower by 745.6998715822702 W/hp and divide by current and decimal efficiency. The inverse efficiency is ฮท = shaft watts / (V ร I), not electrical input divided by shaft output. For AC, electrical real input is V ร I ร PF (single phase) or โ3 ร V ร I ร PF (balanced three phase).
| Horsepower (HP) | Current (A) | Efficiency (%) | Voltage (V) |
|---|---|---|---|
| 1/16 | 5 | 90 | โ 10.357 |
| โ | 5 | 90 | โ 20.714 |
| 1/6 | 5 | 90 | โ 27.619 |
| ยผ | 5 | 90 | โ 41.428 |
| โ | 5 | 90 | โ 55.237 |
| โ | 5 | 90 | โ 62.142 |
| ยฝ | 5 | 90 | โ 82.856 |
| โ | 5 | 90 | โ 103.569 |
| โ | 5 | 90 | โ 110.474 |
| ยพ | 5 | 90 | โ 124.283 |
| โ | 5 | 90 | โ 144.997 |
| 1 | 5 | 90 | โ 165.711 |
| 1ยผ | 5 | 90 | โ 207.139 |
| 1โ | 5 | 90 | โ 220.948 |
| 1ยฝ | 5 | 90 | โ 248.567 |
| 1ยพ | 5 | 90 | โ 289.994 |
| 2 | 5 | 90 | โ 331.422 |
| 2ยฝ | 5 | 90 | โ 414.278 |
| 3 | 5 | 90 | โ 497.133 |
| 4 | 5 | 90 | โ 662.844 |
| DC formula: V = (hp ร 745.6998715822702) / (I ร ฮท). Assumes I = 5 A and ฮท = 0.90; table voltages are rounded. AC requires power factor and the appropriate phase factor. | |||
What is HP To Voltage?
HP to voltage is a steady-state power-balance estimate using shaft output, current, efficiency and supply type. Horsepower alone does not determine voltage or a motorโs nameplate rating. Starting demand, waveform, imbalance and equipment limits require separate assessment.
How to Calculate HP To Voltage?
The following steps outline how to calculate the HP to Voltage.
- First, determine the horsepower (HP).
- Next, determine the current (I).
- Next, determine the efficiency (ฮท).
- Finally, for DC use V = (hp ร 745.6998715822702) / (I ร ฮท), with ฮท as a decimal. For AC, also divide by power factor and, for balanced three-phase, โ3.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Horsepower (HP) = 10
Current (I) = 15 A
Efficiency (ฮท) = 0.85 (enter 85%); DC supply. V = (10 ร 745.6998715822702) / (15 ร 0.85) โ 584.863 V.
