1. What is an AC Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop in a three-phase AC electrical circuit based on current, cable length, resistance, reactance, and power factor angle.

Purpose: It helps electrical engineers and technicians ensure proper voltage levels at load points in power distribution systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( I \) — Current (amps)
• \( L \) — Cable length (meters)
• \( R \) — Resistance per meter (ohms/m)
• \( X \) — Reactance per meter (ohms/m)
• \( φ \) — Power factor angle (degrees)

Explanation: The formula accounts for both resistive and reactive components of the impedance, with the √3 factor for three-phase systems.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures equipment operates within specified voltage tolerances and meets electrical code requirements.

4. Using the Calculator

Tips: Enter the current in amps, cable length in meters, resistance and reactance in ohms/meter, and power factor angle in degrees.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical acceptable voltage drop?
A: Generally 3-5% of supply voltage for feeders, 3% for branch circuits, but check local codes.

Q2: How do I find R and X values?
A: Consult cable manufacturer specifications or standard tables for your cable type and size.

Q3: What's the default power factor angle?
A: 30° (PF ≈ 0.866) is common for many industrial loads, but adjust for your specific application.

Q4: Does this work for single-phase systems?
A: No, for single-phase use VD = 2 × I × L × (R cosφ + X sinφ).

Q5: How does temperature affect the calculation?
A: Higher temperatures increase resistance. For precise calculations, use resistance values at operating temperature.