Precautions for use of the inverter
● Determining if a countermeasure is required
A countermeasure for harmonics is required if the following condition is satisfied:
Outgoing harmonic current > maximum value per 1 kW contract power × contract power
● Harmonic suppression techniques
High power factor
Installation of power
Install an AC reactor (FR-HAL) on the AC side of the inverter or a DC reactor (FR-HEL) on its DC
side, or install both to suppress outgoing harmonic currents.
This converter trims the current waveform to be a sine waveform by switching the rectifier
circuit (converter module) with transistors. Doing so suppresses the generated harmonic
amount significantly. Connect it to the DC area of an inverter. Use the high power factor
converter (FR-HC2) with the accessories that come as standard.
When used with a reactor connected in series, the power factor improving correction
capacitor can absorb harmonic currents.
Use two transformers with a phase angle difference of 30° as in
to provide an effect corresponding to 12 pulses, reducing low-degree harmonic currents.
A capacitor and a reactor are used together to reduce impedances at specific frequencies.
Harmonic currents are expected to be absorbed greatly by using this technique.
This filter detects the current in a circuit generating a harmonic current and generates a
harmonic current equivalent to a difference between that current and a fundamental wave
current to suppress the harmonic current at the detection point. Harmonic currents are
expected to be absorbed greatly by using this technique.
Suppression of harmonics
Power supply harmonics
-Δ and Δ-Δ combinations
3 - 15