AC Voltage Drop Calculator

AC Voltage Drop Formula:

\[ VD = I \times L \times (R \cosφ + X \sinφ) \times 2 \]

Current (I):

amps

Length (L):

meters

Resistance (R):

ohms/m

Reactance (X):

ohms/m

Phase Angle (φ):

degrees

Voltage Drop (VD):

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1. What is AC Voltage Drop?

Definition: AC voltage drop is the reduction in voltage in an electrical circuit due to the resistance and reactance of the conductors.

Purpose: This calculator helps electrical engineers and technicians determine the voltage loss in AC circuits to ensure proper equipment operation.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ VD = I \times L \times (R \cosφ + X \sinφ) \times 2 \]

Where:

\( VD \) — Voltage drop (volts)
\( I \) — Current (amps)
\( L \) — Length of conductor (meters)
\( R \) — Resistance per unit length (ohms/meter)
\( X \) — Reactance per unit length (ohms/meter)
\( φ \) — Phase angle between voltage and current (degrees)

Explanation: The formula accounts for both resistive and reactive components of the impedance, with the factor of 2 for single-phase systems (round-trip distance).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage, prevents overheating of conductors, and maintains system efficiency.

4. Using the Calculator

Tips: Enter the current in amps, conductor length in meters, resistance and reactance values (ohms/m), and phase angle in degrees. Typical values are pre-filled.

5. Frequently Asked Questions (FAQ)

Q1: Why is the phase angle important?
A: The phase angle determines how much of the voltage drop comes from resistance (real power) versus reactance (reactive power).

Q2: What are typical R and X values?
A: For copper conductors, R is typically 0.0005 Ω/m and X is about 0.0002 Ω/m, but varies with conductor size and spacing.

Q3: When would I use this calculator?
A: For sizing conductors in AC power distribution systems to ensure voltage drop stays within acceptable limits (usually 3-5%).

Q4: Does this work for three-phase systems?
A: For three-phase, remove the factor of 2 and use line-to-line voltage drop calculations.

Q5: How does conductor material affect results?
A: Different materials have different resistance values - copper has lower resistance than aluminum for the same size.