Three-phase electrical systems are widely used in industries, factories, commercial buildings, solar systems, and data centers. Electrical engineers frequently need to calculate current, power, voltage, and power factor for motors, transformers, and industrial loads.
In this tutorial, you will learn how to build a professional Three-Phase Power Calculator using:
- HTML
- CSS
- JavaScript
This project is beginner-friendly and works directly in the browser without any external library.
Figure-1: Three-Phase Power Calculator Preview
Features of This Project
- Calculate three-phase current instantly
- Supports power factor input
- Professional responsive design
- Real engineering calculation formula
- Pure JavaScript project
- Mobile-friendly UI
Understanding the Three-Phase Power Formula
The standard three-phase power equation is:
P = √3 × V × I × cosφ
| Symbol | Meaning |
|---|---|
| P | Power (Watts) |
| V | Line Voltage |
| I | Line Current |
| cosφ | Power Factor |
To calculate current:
I = P / (√3 × V × cosφ)
Project Structure
index.html style.css script.js
Step 1 — Create the HTML File
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Three-Phase Power Calculator</title>
<link rel="stylesheet" href="style.css">
</head>
<body>
<div class="container">
<h1>Three-Phase Power Calculator</h1>
<div class="input-group">
<label>Power (kW)</label>
<input type="number" id="power" placeholder="Enter Power">
</div>
<div class="input-group">
<label>Voltage (V)</label>
<input type="number" id="voltage" placeholder="Enter Voltage">
</div>
<div class="input-group">
<label>Power Factor</label>
<input type="number" id="pf" step="0.01" placeholder="Enter PF">
</div>
<button onclick="calculateCurrent()">
Calculate Current
</button>
<div class="result">
<h2 id="output">Current: 0 A</h2>
</div>
</div>
<script src="script.js"></script>
</body>
</html>
Step 2 — Add CSS Styling
style.css
body{
font-family: Arial, sans-serif;
background:#f4f4f4;
display:flex;
justify-content:center;
align-items:center;
height:100vh;
}
.container{
background:white;
padding:30px;
width:350px;
border-radius:10px;
box-shadow:0 0 10px rgba(0,0,0,0.2);
}
h1{
text-align:center;
margin-bottom:20px;
}
.input-group{
margin-bottom:15px;
}
label{
display:block;
margin-bottom:5px;
font-weight:bold;
}
input{
width:100%;
padding:10px;
border:1px solid #ccc;
border-radius:5px;
}
button{
width:100%;
padding:12px;
background:#007bff;
color:white;
border:none;
border-radius:5px;
cursor:pointer;
font-size:16px;
}
button:hover{
background:#0056b3;
}
.result{
margin-top:20px;
text-align:center;
}
Step 3 — Add JavaScript Logic
script.js
function calculateCurrent(){
let power = document.getElementById("power").value;
let voltage = document.getElementById("voltage").value;
let pf = document.getElementById("pf").value;
// Convert kW to Watts
power = power * 1000;
// Three-phase current calculation
let current = power / (1.732 * voltage * pf);
// Display result
document.getElementById("output").innerHTML =
"Current: " + current.toFixed(2) + " A";
}
How the JavaScript Works
Getting Input Values
document.getElementById("power").value
This reads the value entered by the user.
Converting kW to Watts
power = power * 1000;
The formula uses Watts, so kW must be converted.
Current Formula
current = power / (1.732 * voltage * pf);
Here:
- 1.732 = √3
- Voltage = line voltage
- PF = power factor
Example Calculation
Suppose:
- Power = 15 kW
- Voltage = 415 V
- Power Factor = 0.85
Then:
I = 15000 / (1.732 × 415 × 0.85)
Current ≈ 24.55 A
Applications of This Calculator
- Industrial motor load calculation
- Transformer sizing
- Generator sizing
- Solar inverter current calculation
- Electrical panel design
- Cable size estimation
Common Beginner Mistakes
1. Forgetting kW to Watt Conversion
Wrong:
current = power / (1.732 * voltage * pf);
Correct:
power = power * 1000;
2. Using Incorrect Voltage
For three-phase systems, use line voltage such as:
- 400V
- 415V
- 440V
Advanced Features You Can Add
- kVA Calculator
- Power Factor Correction
- Voltage Drop Calculator
- Cable Size Recommendation
- Dark Mode
- PDF Report Export
- Real-time Graph
SEO Keywords
- Three phase calculator JavaScript
- Electrical engineering JavaScript project
- Three phase current calculator
- Power calculator project
- Industrial power calculator
- JavaScript engineering tools
FAQs
What is a three-phase power system?
A three-phase power system is an AC electrical system using three alternating currents with phase differences of 120 degrees. It is commonly used in industries and commercial applications.
Why is √3 used in the formula?
The value √3 (1.732) comes from the mathematical relationship between line voltage and phase voltage in a three-phase system.
Can this calculator work for motors?
Yes. This calculator can estimate motor current based on power, voltage, and power factor.
What is power factor?
Power factor represents the efficiency of electrical power usage. It is the ratio of real power to apparent power.
Can I use this project for my portfolio?
Yes. This is an excellent beginner electrical engineering + JavaScript portfolio project.
What programming language is used in this project?
This project uses:
- HTML
- CSS
- JavaScript
Can I add more electrical calculations?
Yes. You can add:
- kVA calculations
- Voltage drop calculations
- Cable sizing
- Transformer efficiency
- Power factor correction
Conclusion
You have successfully built a complete Three-Phase Power Calculator using JavaScript. This project combines electrical engineering concepts with web development and is an excellent real-world engineering tool.
You can further improve the calculator by adding advanced electrical calculations, responsive UI components, and industrial engineering features.
