Longcircuit
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**Subject: High THD on 2nd and 3rd Harmonics of a 5kW Single-Phase UPS**
Hi everyone,
I'm measuring the input current harmonics on a single-phase 5kW UPS with a 120V AC, 60Hz input. I noticed that the Total Harmonic Distortion (THD) is high specifically on the 2nd and 3rd harmonics.the ups has a boost pfc and isolation transformer on input.
**My questions are:**
1. In general, aren't even harmonics (like the 2nd harmonic) usually a sign of a DC offset or asymmetry in the waveform?
2. Can such low-frequency harmonics be effectively filtered using an LC filter, or would other methods be more appropriate?
Thanks in advance for your insights!
Hi everyone,
I'm measuring the input current harmonics on a single-phase 5kW UPS with a 120V AC, 60Hz input. I noticed that the Total Harmonic Distortion (THD) is high specifically on the 2nd and 3rd harmonics.the ups has a boost pfc and isolation transformer on input.
**My questions are:**
1. In general, aren't even harmonics (like the 2nd harmonic) usually a sign of a DC offset or asymmetry in the waveform?
2. Can such low-frequency harmonics be effectively filtered using an LC filter, or would other methods be more appropriate?
Thanks in advance for your insights!