Three-Phase V-I-P Calculator

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Line-to-line voltage

Three-phase voltage

Line current

Current per phase

Power

Active power

Power units

Power factor (cos φ)

Range: 0 to 1

Efficiency

Motor/equipment efficiency

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Title

Description

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Company name

Project number

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Project name

Client company

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Your Company

Calculation No.: Calc-001
Revision: A
Description:
Created By: Engineer Name

Project: Project Name
Project No.: P001
Client: Client Name

Input Parameters

The following design parameters were considered for this calculation:

Parameter	Symbol	Value	Notes
Voltage (Phase to Phase)	V_L-L	415 V	3-Phase System
Active Power	P	15 kW	Load
Efficiency	η	100	At rated load
Power Factor	PF	0.85	Lagging

Calculations

All calculations were performed in accordance with IEC standards and good engineering practice.

Current Calculation

The full-load current is calculated using the formula: This represents the phase current drawn by the load.

Formula: $$ \begin{aligned} I_{(A)} &= \frac{\left( \frac{P}{\eta} \right) \times 1{,}000}{\sqrt{3} \times V_{L-L(V)} \times PF} \\ &= \frac{\left( \frac{15}{1} \right) \times 1{,}000}{\sqrt{3} \times 415 \times 0.85} \\ &= 24.6 \; Amps \end{aligned} $$

Phase Angle Calculation

The phase angle is calculated using the formula:

Formula: $$ \begin{aligned} \theta &= \cos^{-1}(PF) \times \frac{180}{\pi} \\ &= \cos^{-1}(0.85) \times \frac{180}{3.142} \\ &= 31.8^\circ \end{aligned} $$

Three-Phase Voltage and Current Phasors

The phasor diagram shows the three-phase voltage and current phasors with the phase angle (φ) between them. Each phase (A, B, C) is separated by 120°. Solid lines represent voltage phasors, while dashed lines represent current phasors lagging behind voltage.

Figure 1: Three-phase phasor diagram showing voltage and current relationships

Three-Phase Power Relationships

The power triangle illustrates the relationship between active power (P), reactive power (Q), and apparent power (S). Active power does useful work, reactive power oscillates between source and load, and apparent power is the vector sum of both.

Figure 2: Power triangle showing P, Q, and S relationships

Summary of Results

Below is the summary of calculated values for ease of reference:

Parameter	Symbol	Value	Notes
Current (Phase)	I_p	24.6 A	Phase Current
Apparent Power	S	17.6 kVA	Load
Active Power	P	15 kW	Load
Reactive Power	Q	9.3 kVAr	Load

Approval:

This calculation has been reviewed and approved by:

Created By
Engineer Name
Date: ..........................

Checked
By: .............................
Date: ..........................

Approved
By: .............................
Date: ..........................

Client Approved
By: .............................
Date: ..........................

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