Reactor %Z to mH Calculator
Convert a reactor’s percent impedance to inductance per phase, or an inductance back to percent impedance, at the reactor’s rated current.
Inputs
Results
| Base impedance | – |
| Reactance per phase | – |
| Inductance per phase | – |
| Percent impedance | – |
| Voltage drop at rated current | – |
Three phase: Zbase = VLL ÷ (√3 × I). Single phase: Zbase = V ÷ I.
X = (%Z ÷ 100) × Zbase, L = X ÷ (2πf). Voltage drop is across the reactor, per phase (line-to-neutral for three phase).
Choosing an impedance
Line reactors are commonly offered at 3% and 5%. Higher impedance reduces input harmonic current more and attenuates line transients better, but it also drops more voltage at full load. Load reactors are most often 3%. Read more on our reactors & inductors page, or check cable length with the motor lead-length guide.
DC link chokes are specified by inductance and DC current for a particular drive, so this percent-impedance conversion does not apply to them directly.
For preliminary sizing only. The drive manufacturer’s requirements and the reactor manufacturer’s ratings govern the final selection.