HP to AMPS & AMPS to HP CALCULATOR

 

HP to Amps or Amps to HP calculator are mainly used for motor circuits. HP is used to express output power and Amps expresses full load Amps or rated input current.

Choose what to calculate


Horsepower
HP
Connection Type
Volts
V
Efficiency
%
Choose what to calculate


Current
Amps
Connection Type
Volts
V
Efficiency
%

What is Horsepower:

Horsepower is the unit used to express mechanical output power of motor and engine. It is defined as the amount of power that is used to lift 745.7 N of weight to 1m in 1s by a horse.

1 HP=745.7 watts~746 watts

HP to Amps or Amps to HP calculator parameter:

  • Choose what to calculate: HP to Amps or Amps to HP
  • if HP to amps selected: rated amps
  • If Amps to HP selected: rated HP
  • Option: For DC, 1∅, 2∅, and 3∅,  motors
  • Rated voltage (volts): for 3 phase voltages, line to line and line to neutral option is provided
  • Efficiency: given in percentage (%)
  • Power factor: in percentage or unit (specified for single phase, two phase and three phase)

Converting HP to Amps:

A general step for converting HP to amps for all types of circuit is given as:

Step1: converting HP to watts, by multiplying HP with 746.

Step2: dividing watts with voltage(V) and efficiency to get the required amps(I).

For DC circuits:

The formula for DC circuits is given below.

I =
HP * 746 / V * (Efficiency(%)/100)

For 1 phase AC circuit:

The formula for single phase AC circuit is same as DC with an addition of power factor (p.f) which is given as:

I =
HP * 746 / V * (Efficiency(%)/100) * PF

For 2 phase AC circuits::

The formula for two phase AC circuit is same as single phase AC circuit with an additional factor of 2 which is given as:

=
HP * 746 / V * (Efficiency(%)/100) * PF * 2

For 3 phase AC circuits:

The formula for three phase AC circuit is same as two phase AC circuit but instead of 2 we use square root 3 (~1.73) when voltage is expressed in terms of line to line (Vll) which is given as:

=
HP * 746 / Vll * (Efficiency(%)/100) * PF * 1.73

When voltage is expressed in terms of line to neutral then we use 3 instead of 1.73.

=
HP * 746 / Vln * (Efficiency(%)/100) * PF * 3

Converting Amps to HP:

A general step for converting amps to HP for all types of circuit is given as:

Step1: finding power (in watts) by multiplying voltage(V), current(I) and efficiency (%).

Step2: converting watts to HP, by dividing watts with 746.

For DC circuits:

The formula for DC circuits is given below.

P =
I * V * (Efficiency(%)/100) / 746

For 1 phase AC circuit:

The formula for single phase AC circuit is same as DC with an addition of power factor (p.f) which is given as:

=
I * V * (Efficiency(%)/100) * PF / 746

For 2 phase AC circuits:

The formula for two phase AC circuit is same as single phase AC circuit with an additional factor of 2 which is given as:

=
I * V * (Efficiency(%)/100) * PF * 2 / 746

For 3 phase AC circuits:

The formula for three phase AC circuit is same as two phase AC circuit but instead of 2 we use square root 3 (~1.73) when voltage is expressed in terms of line to line (Vll) which is given as:

=
I * Vll * (Efficiency(%)/100) * PF * 1.73 / 746

When voltage is expressed in terms of line to neutral then we use 3 instead of 1.73.

=
I * Vln * (Efficiency(%)/100) * PF * 3 / 746

Note

In the above formulas:

  • As efficiency is expressed in percentage (%) it must be divided by 100 to get the required answer.
  • power factor (p.f) is given in form of unit, ranging from 0 to 1 (for example: 0.8, 0.9). If p.f is expressed in terms of percentage then it is first converted into units by dividing percentage power factor by 100 and then its value is given in the formula.

Solved Example:

For DC circuits:

HP to Amps conversion:

Consider a DC motor that has the following data:

Given:

Voltage =120 V

Efficiency =90 %

Power= 3 HP

Required:

Current (I)=? (Amps)

Solution:

From DC circuit formula for HP to Amps conversion:

=
3 * 746 / 120 * (90/100)
=20.722 Amps

Amps to HP conversion:

Consider a motor that has the following data:

Given:

Voltage =120 V

Efficiency =90 %

Current (I)=15 Amps

Required:

Power=? (HP)

Solution:

From DC circuit formula for Amps to HP conversion:

P =
15 * 120 * (90/100) / 746
=2.17HP

For 1 phase circuits:

HP to Amps conversion:

Consider a single phase AC motor that has the following data:

Given:

Voltage =230 V

Efficiency =90 %

Power= 2 HP

Power factor (p.f) =0.92

Required:

Current (I)=? (Amps)

Solution:

From single phase AC circuit formula for HP to Amps conversion:

=
2 * 746 / 230 * (90/100) * 0.92
=7.834 Amps

Amps to HP conversion:

Consider a single phase motor that has the following data:

Given:

Voltage =230 V

Efficiency =90 %

Current (I)=20 Amps

Power factor (p.f) =0.92

Required:

Power=? (HP)

Solution:

From single phase AC circuit formula for Amps to HP conversion:

P =
20 * 230 * (90/100) * 0.92 / 746
=5.11HP

For 2 phase circuits:

HP to Amps conversion:

Consider a two phase motor that has the following data:

Given:

Voltage =220 V

Efficiency =88 %

Power= 2 HP

Power factor (p.f) =0.9

Required:

Current (I)=? (Amps)

Solution:

From two phase AC circuit formula for HP to Amps conversion:

=
2 * 746 / 220 * (88/100) * 0.9 * 2
=4.281Amps

Amps to HP conversion:

Consider a two phase motor that has the following data:

Given:

Voltage =220 V

Efficiency =88 %

Current (I)=15 Amps

Power factor (p.f) =0.9

Required:

Power=? (HP)

Solution:

From two phase AC circuit formula for Amps to HP conversion:

=
2 * 220 * 15 * (88/100)* 0.9 / 746
=7.01 HP

For 3 phase circuits:

HP to Amps conversion:

Consider a three phase motor that has the following data:

Given:

Voltage (line to line) =480 V

Efficiency =90 %

Power= 25 HP

Power factor (p.f) =0.9

Required:

Current (I)=? (Amps)

Solution:

From three phase AC circuit formula for HP to Amps conversion:

I =
25 * 746 / 1.73 * 480 * (90/100) * 0.9
=27.728Amps

If we change voltage from line to line to line to neutral, for example: V (line to neutral) =277.13 V

Then we will be calculating it using formula of 3 phase AC circuit when voltage is given as line to neutral that is:

I =
25 * 746 / 3 * 277.13 * (90/100) * 0.9
=27.694Amps

Amps to HP conversion:

Consider a three phase motor that has the following data:

Given:

Voltage =480 V

Efficiency =90 %

Current (I)=25 Amps

Power factor (p.f) =0.9

Required:

Power=? (HP)

Solution:

From three phase AC circuit formula for Amps to HP conversion:

=
1.73 * 480 * 25 * (90/100) * 0.9 / 746
=22.54 HP

If we change voltage from line to line to line to neutral, for example: V (line to neutral) =277.13 V (480/1.73)

Then we will be calculating it using formula of 3 phase AC circuit when voltage is given as line to neutral that is:

P =
3 * 277 * 25 * (90/100) * 0.9 / 746
= 22.56HP