HP to AMPS & AMPS to HP CALCULATOR

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.

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.

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:

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:

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:

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

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.

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:

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:

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:

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

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:

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:

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:

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:

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:

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:

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:

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:

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:

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: