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EMC and leakage currents
3
PRECAUTIONS FOR USE OF THE INVERTER
3)Harmonic suppression technique requirement
If the outgoing harmonic current is higher than the maximum value per 1kW (contract power) × contract power, a
harmonic suppression technique is required.
4)Harmonic suppression techniques
No. Item Description
1
Reactor installation
(FR-HAL, FR-HEL)
Install an AC reactor (FR-HAL) on the AC side of the inverter or a DC reactor (FR-HEL) on
its DC side or both to suppress outgoing harmonic currents.
2
High power factor converter
(FR-HC, MT-HC)
The converter circuit is switched on-off to convert an input current waveform into a sine
wave, suppressing harmonic currents substantially. The high power factor converter (FR-
HC, MT-HC) is used with the standard accessory.
3
Installation of power factor
improving capacitor
When used with a series reactor, the power factor improving capacitor has an effect of
absorbing harmonic currents.
4
Transformer multi-phase
operation
Use two transformers with a phase angle difference of 30° as in - , - combination
to provide an effect corresponding to 12 pulses, reducing low-degree harmonic currents.
5
Passive filter
(AC filter)
A capacitor and a reactor are used together to reduce impedances at specific frequencies,
producing a great effect of absorbing harmonic currents.
6Active filter
This filter detects the current of 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 a harmonic current at a detection point, providing a great effect of
absorbing harmonic currents.