HP to Amps formulas are used to calculate current provided that HP (horsepower) is known in any circuit. Given below are the formulas:

HP to Amps
| Formula |

In case of DC | (HP x 746)/(E x %Efficiency) |

Single phase AC | (HP x 746)/(E x %Efficiency x PF) |

Two phase four wire | (HP x 746)/(E x %Efficiency x PF x 2) |

Three phase | (HP x 746)/(E x %Efficiency x PF x 1.73) |

**DC Circuit**

Example: How much current a 0.5 HP DC motor having efficiency rating of 95% will draw at rated voltage of 12 volts.

Solution: I (DC) = (0.5 * 746) / (12 volts * 0.95)

I (DC) = 32.7

**Single Phase AC Circuit**

Example: A single phase 1/2 HP, 120 volt AC motor has efficiency rating of 90%. Find the current drawing by motor at power factor of 85%.

Solution: I (Single phase AC) = (0.5 * 746)/(120 * 0.9 * 0.85)

I (Single phase AC) = 4.06 Amps

**Two phase four wire system**

Example: Determine the current drawn by a two phase 1 HP, 230-volt motor having an efficiency rating of 90% and a power factor of 83%

Solution: I (Two phase AC) = (1 * 746)/(230 * 0.9 * 0.83 * 2)

I (Two phase) = 2.17 Amps

**Three phase system**

Example: A three phase, 1 HP, 230-volt motor having EF rating 85% operates at PF of 80%. Find the current drawn by the motor.

Solution: I (Three phase AC) = (1 * 746)/(230 * 0.85 * 0.8 * 1.73)

I (Three phase AC) = 2.75 Amps

So that was all about amps calculation from HP.

Let’s revise the formulas once: