Power formula calculator (step-by-step example)
3-phase power formula, P =√3* V * I * pf, 1-phase power formula, P = V * I * pdf,
Every day, we use power formulas to calculate the power requirements of various loads, including motors and lighting.
In this article, I will guide you through the calculation of power step by step and provide the relevant power formula.
Three-phase power formula
The calculation formula of power in the  three-phase circuit is:
P =√3× VI× ×IL× because (θ)
Location:
P is power in watts (W).
√3 equals √3, which is approximately equal to 1.732.
VL is the line-to-line voltage in volts (V).
IL is the line current in ampere (a).
Cos (θ) is the power factor (cosine of the phase angle difference between voltage and current).
In a three-phase system, power is not just the product of line-to-line voltage (VL) and line current (IL) as in a single-phase system.
To find the real power, you need to multiply by the root number 3 and the power factor (cos(θ)).
Three-phase power formula calculator
Let's go through an example of a three-phase load calculation step by step.
Example: Suppose you have a three-phase electrical system with the following parameters:
Line voltage (VL)： 400 volts.
Line current (IL)： 50 Amps
Power factor (cos (θ)): 0.9
Calculate the power (p) in watts (w).
P=1.73×VL×IL×cos (θ)P =1.73×VL×IL×cos （θ）
P=1.73×400 v×50 a×0.9, P≈69,570w
Single-phase power formula calculator
The calculation formula for single-phase power in the circuit is:
P = V×× because (θ)
Location:
P is power in watts (W).
V is voltage, and the unit is v.
Iams the current in amperes (A).
Cos (θ) is the power factor.
This power formula calculator calculates the actual power (in watts) of a single-phase circuit. The power factor (cos (θ)) indicates the phase angle difference between voltage and current and shows how electric energy can be effectively converted into useful work.
Example of a single-phase power formula calculator
Let's look at an example of calculating single-phase power step by step.
Example: Suppose you have a single-phase circuit with the following parameters:
Voltage (V): 120 volts.
Current (I): 5 amps
Power factor (cos (θ)): 0.9
Calculate the power (p) in watts (w).
P = V×I×cos （θ）
P=120 v×5 a×0.9 = 540 w