HP to Amps formula is used to calculate current from horsepower in single and three phase ac circuits as well as in DC circuits. The basic formulas for the calculations are:

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### HP to Amps in DC Circuits

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Formula: DC Amps = [HP * 746] / [E * % Efficiency]
A 1/8 HP, 100 volts dc motor has an efficiency rating of 95%. Find the amps.

Solution: In our present case Single phase Amps = [1/8 * 746] / [100 * 0.95] = 0.98 Amps

### HP to Amps in Single Phase AC Circuits

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Formula: Single phase Amps = [HP * 746] / [E * % Efficiency * PF]
A 1/2 HP, 100 volts single phase motor has an efficiency rating of 87%. The power factor of the motor is 0.87. Find the current.

Solution: In our present case Single phase Amps = [1/2 * 746] / [100 * 0.87 * 0.87] = 4.92 Amps

### HP to Amps in 2 Phase AC Circuits

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Formula: 2 phase Amps = [HP * 746] / [E * % Efficiency * PF * 2]
A 1/8 HP, 120 volts motor has an efficiency rating of 90%. The power factor of the motor is 0.82. Find the current flowing through the motor.

Solution: In our present case 2 phase Amps = [1/8 * 746] / [120 * 0.9 * 0.82 * 2] = 0.526 Amps

### HP to Amps in 3 Phase AC Circuits

Formula: 3 phase Amps = [HP * 746] / [E * % Efficiency * PF * 1.73]

A 1/4 HP, 220 volts motor has an efficiency rating of 95%. The power factor of the motor is 0.85. Find the current flowing through the motor.

Solution: In our present case 3 phase Amps = [1/4 * 746] / [220 * 0.95 * 0.85 * 1.73] = 0.606 Amps

In the image above it shows [1 W = 745.7 HP], but I believe it should be [1 HP = 745.7 W].

ReplyDeletewhere did the 1.73 come from

ReplyDeletesquare root of 3

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