Harmonic Filter Calculator
Calculate the tuning capacitor and inductor values for a single-tuned passive harmonic filter.
Tuning Frequency
300 Hz
Tuning Frequency vs Fundamental Frequency
Single-Tuned Harmonic Filter Design
A series LC filter tuned to a specific harmonic frequency provides a low-impedance path that diverts harmonic current away from the system.
Design Steps
1. Capacitive reactance at fundamental: Xc = V^2 / kVAR 2. Inductive reactance at fundamental: Xl = Xc / n^2 3. Capacitance: C = 1 / (omega x Xc) 4. Inductance: L = Xl / omega
Where n is the harmonic order and omega = 2 x pi x f_fundamental.
Filters are typically tuned slightly below the target harmonic (e.g., 4.7th instead of 5th) to avoid resonance with system impedance.
Example Calculation
5th harmonic filter, 50 kVAR, 480 V, 60 Hz system.
- 01Tuning frequency: 60 x 5 = 300 Hz
- 02Xc at 60 Hz: 480^2 / 50000 = 4.608 ohms
- 03Xl at 60 Hz: 4.608 / 25 = 0.184 ohms
- 04C = 1 / (377 x 4.608) = 575.7 microfarads
- 05L = 0.184 / 377 = 0.49 mH
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