Harmonic suppression and current limiting — the unsung protector of your LT network.
Variable frequency drives, UPS systems, and switched-mode power supplies all draw current in pulses rather than as a smooth sine wave. Those current pulses contain harmonics — primarily 5th and 7th order (250 Hz and 350 Hz in a 50 Hz system) — that flow back into the supply network, heating transformers and cables, causing nuisance relay trips, and interfering with metering and communications equipment. A line reactor (choke) connected in series at the drive input limits the rate of current rise, reducing the harmonic content in the drawn current by 30–50% without any tuning or maintenance.
Sakthi manufactures iron-core chokes on CRGO laminated cores for 415V LT applications and air-core reactors for resonant filter circuits. The inductance, current rating, and percentage impedance are calculated from the drive rating and supply impedance — there is no single standard rating that suits every installation. Sakthi's engineering team will calculate the correct reactor specification from the VFD nameplate data and supply transformer impedance; contact us with these details for a quotation.
Typical applications
Installed as line reactors at VFD inputs to reduce 5th and 7th harmonic currents and limit total harmonic distortion (THD).
Limits fault current at the interconnection point in LT panels, reducing available fault level and protecting switchgear.
Protects variable frequency drives from voltage spikes, commutation notches, and high dv/dt from the upstream supply network.
Used as detuned reactors in APFC banks to prevent harmonic resonance between capacitor banks and system impedance.
Tell us your spec. We'll build to it.
Share your ratio, accuracy class, burden and standard — our engineering team will quote the right unit.