Model input current harmonics with flexible entries now. See results above, export reports in seconds. Tune drives, avoid overheating, and meet distortion targets easily.
| Order (h) | Magnitude | Unit | Notes |
|---|---|---|---|
| 1 | 50 | A RMS | Fundamental (reference) |
| 5 | 10 | % of I1 | Common for 6-pulse converters |
| 7 | 7 | % of I1 | Often paired with 5th harmonic |
| 11 | 4 | % of I1 | Higher-order component |
| 13 | 3 | % of I1 | Higher-order component |
Nonlinear converters draw current in pulses rather than smooth sine waves. Those pulses create 5th, 7th, 11th, and 13th components that raise RMS heating. Even when real power is unchanged, wiring and protective devices may run hotter because Irms_total increases with the square‑sum of harmonic currents. In facilities with many drives, the cumulative distortion can elevate neutral currents and audible noise.
This calculator reports THD as the harmonic RMS divided by the fundamental current. For example, with I1 = 50 A and harmonic RMS of 8 A, THD is 16%. Total RMS becomes √(50² + 8²) = 50.64 A, a 1.28% rise that still affects copper loss because loss scales with current squared.
When you provide IL, the tool computes TDD, which compares harmonic RMS to the maximum demand level. If harmonic RMS is 8 A and IL is 80 A, TDD is 10%. TDD is useful where limits are tied to system strength and demand, not merely the present fundamental magnitude. Enter IL from demand records or measured peak operating windows for a consistent baseline.
K‑factor weights higher orders by h², reflecting increased eddy and stray losses. If the 13th harmonic is small but present, its contribution is multiplied by 169. A rising K‑factor suggests selecting a transformer rating that tolerates harmonic heating or applying mitigation upstream. Use K‑factor alongside loading and ambient conditions to avoid unnecessary overdesign.
The Plotly chart visualizes the spectrum as a bar plot of Ih versus harmonic order. A clear 5th/7th dominance often points to six‑pulse rectification. A flatter, wide spectrum can indicate switching supplies or mixed loads. Compare before‑and‑after plots to confirm that mitigation reduces targeted orders without amplifying others.
Export CSV for detailed engineering records and trend comparison across sites. Export PDF for a compact attachment in design reviews. After modeling, validate with power quality measurements, then reassess conductor sizing, capacitor resonance risk, and protective device settings before implementing mitigation. If results are high, evaluate line reactors or harmonic filters and recheck distortion at the point of common coupling for decision making.
Provide the fundamental RMS current (I1) and at least one harmonic order with a magnitude. You may enter harmonics as percent of I1 or as RMS amps.
THD references harmonic RMS to the fundamental current. TDD references harmonic RMS to the demand current IL. TDD is helpful when limits depend on demand rather than present operating point.
Yes. If you add the same order more than once, the calculator combines them using an RMS square‑sum, which matches how independent components add for heating.
It is an engineering approximation based on weighting harmonic currents by order squared. Use it as a screening indicator alongside transformer data, loading, and temperature measurements.
RMS reflects heating. Harmonic currents add in quadrature, so total RMS equals √(I1² + ΣIh²). Any additional harmonic content increases conductor and device losses.
Use the bar chart to identify dominant orders, then target mitigation accordingly. Compare plots before and after changes to confirm reductions and ensure you did not introduce new peaks.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.