3 Phase Power Calculator

3-Phase Power Calculator

function calculatePower() { var voltage = parseFloat(document.getElementById('voltageInput').value); var current = parseFloat(document.getElementById('currentInput').value); var powerFactor = parseFloat(document.getElementById('powerFactorInput').value); var efficiency = parseFloat(document.getElementById('efficiencyInput').value); var resultDiv = document.getElementById('result'); var apparentPowerResult = document.getElementById('apparentPowerResult'); var realPowerResult = document.getElementById('realPowerResult'); var reactivePowerResult = document.getElementById('reactivePowerResult'); var outputPowerResult = document.getElementById('outputPowerResult'); // Input validation if (isNaN(voltage) || voltage <= 0) { alert('Please enter a valid positive Line-to-Line Voltage.'); resultDiv.style.display = 'none'; return; } if (isNaN(current) || current <= 0) { alert('Please enter a valid positive Line Current.'); resultDiv.style.display = 'none'; return; } if (isNaN(powerFactor) || powerFactor 1) { alert('Please enter a valid Power Factor between 0 and 1.'); resultDiv.style.display = 'none'; return; } if (isNaN(efficiency) || efficiency 100) { alert('Please enter a valid Efficiency between 0 and 100.'); resultDiv.style.display = 'none'; return; } // Calculations var sqrt3 = Math.sqrt(3); // Apparent Power (S) = sqrt(3) * V_line * I_line var apparentPower = sqrt3 * voltage * current; // Real Power (P) = sqrt(3) * V_line * I_line * PF var realPower = apparentPower * powerFactor; // Reactive Power (Q) = sqrt(3) * V_line * I_line * sin(acos(PF)) // Or Q = sqrt(S^2 – P^2) var reactivePower = Math.sqrt(Math.pow(apparentPower, 2) – Math.pow(realPower, 2)); // Output Power (P_out) = Real Power * Efficiency / 100 var outputPower = realPower * (efficiency / 100); // Display results apparentPowerResult.textContent = apparentPower.toFixed(2); realPowerResult.textContent = realPower.toFixed(2); reactivePowerResult.textContent = reactivePower.toFixed(2); outputPowerResult.textContent = outputPower.toFixed(2); resultDiv.style.display = 'block'; }

Understanding 3-Phase Power and Its Calculation

Three-phase power is a common method of alternating current (AC) electric power generation, transmission, and distribution. It is the most common method used by electric power grids worldwide to transfer power. It is also used to power large motors and other heavy loads. Compared to single-phase AC power, three-phase power offers significant advantages, including more efficient power transmission, smoother power delivery, and the ability to start motors without additional starting mechanisms.

Key Concepts in 3-Phase Power

To accurately calculate 3-phase power, several key electrical parameters must be understood:

• Line-to-Line Voltage (V): This is the voltage measured between any two of the three phase conductors. In a balanced 3-phase system, this voltage is typically consistent across all pairs of phases.
• Line Current (I): This is the current flowing through each of the three phase conductors. In a balanced system, the current in each line is equal.
• Power Factor (PF): The power factor is a dimensionless number between 0 and 1 that represents the ratio of real power (work-producing power) to apparent power (total power delivered). A power factor of 1 indicates that all the current supplied is being used to do useful work, while a lower power factor indicates that more current is required to deliver the same amount of useful power, often due to reactive loads like motors or transformers.
• Efficiency (%): Efficiency is the ratio of useful power output to the total power input, expressed as a percentage. In electrical systems, not all the real power consumed by a device is converted into useful work; some is lost as heat. This calculator allows you to account for this loss to determine the actual output power.

Types of Power in 3-Phase Systems

When dealing with AC circuits, especially 3-phase, we distinguish between three types of power:

• Apparent Power (S): Measured in Volt-Amperes (VA), this is the total power flowing in the circuit, including both real and reactive power. It is the product of the voltage and current without considering the phase angle between them.
• Real Power (P): Also known as active power, measured in Watts (W), this is the actual power consumed by the load and converted into useful work (e.g., heat, light, mechanical energy). It is the power that performs work.
• Reactive Power (Q): Measured in Volt-Ampere Reactive (VAR), this is the power that oscillates between the source and the load, building up and collapsing magnetic or electric fields. It does not perform useful work but is necessary for the operation of inductive (e.g., motors, transformers) and capacitive loads.

How the 3-Phase Power Calculator Works

Our 3-Phase Power Calculator uses the following standard formulas to determine the various power components:

1. Apparent Power (S):
   S = √3 × Vline × Iline
   Where:
   • √3 is approximately 1.732
   • Vline is the Line-to-Line Voltage in Volts
   • Iline is the Line Current in Amperes
2. Real Power (P):
   P = √3 × Vline × Iline × PF
   Or, more simply: P = S × PF
   Where:
   • PF is the Power Factor
3. Reactive Power (Q):
   Q = √3 × Vline × Iline × sin(φ)
   Where φ is the phase angle, and cos(φ) = PF.
   Alternatively, using the power triangle relationship: Q = √(S2 - P2)
4. Output Power (P_out):
   Pout = P × (Efficiency / 100)
   Where:
   • Efficiency is the efficiency percentage (e.g., 90 for 90%)

Example Calculation

Let's say you have a 3-phase motor with the following specifications:

• Line-to-Line Voltage (V): 400 Volts
• Line Current (I): 50 Amperes
• Power Factor (PF): 0.85
• Efficiency: 90%

Using the calculator:

1. Apparent Power (S):
   S = 1.732 × 400 V × 50 A = 34640 VA
2. Real Power (P):
   P = 34640 VA × 0.85 = 29444 Watts
3. Reactive Power (Q):
   Q = √(346402 - 294442) ≈ 18200.5 VAR
4. Output Power (P_out):
   Pout = 29444 W × (90 / 100) = 26499.6 Watts

This calculator provides a quick and accurate way to determine these critical power values for your 3-phase electrical systems, aiding in design, troubleshooting, and energy management.