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Causes of harmonics 
• 
General electrical equipment internally con- 
verts AC input power (commercial power) into 
DC power. At this time, harmonic currents 
occur because of the difference in the current 
flow direction between AC power and DC 
power. 
• 
In an AC-to-DC power conversion, the rectifier 
converts the input power into a unidirectional 
voltage, which is then smoothened by the 
capacitor. As a result, the current charged into 
the capacitor has a waveform that contains 
harmonic components. 
• 
This inverter also performs an AC-to-DC con- 
version as with other electrical equipment, 
which allows current with harmonic compo- 
nents to flow. In particular, the inverter has 
more current than other equipment, so the 
number of harmonic components in current is 
larger. 
 
 
 
 
 
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DC/AC reactor 
To suppress harmonic currents, use the DC (direct current) and AC (alternating current) reactors. 
The DC/AC reactor functions to suppress a steep change in the current. 
The DC reactor has a higher harmonics suppression ability, so even higher suppression ability can 
be expected when used in conjunction with the AC reactor. 
Suppressing harmonic currents also leads to the improvement in the power factor on the input or 
output side of the inverter. 
 
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Before wiring 
The DC reactor is connected to the DC power supply located inside the inverter. Before wiring, be 
sure to turn off the power supply and make sure that the charge indicator is not lit. 
Do not touch the interior of the inverter during inverter opertaion. Doing so may result in electric 
shock or burn injury. 
 
By factory default, a short-circuit bar is connected between the terminals +1 and –P/+. Before con- 
necting the DC reactor, remove this short-circuit bar. 
Note that the length of the DC reactor connection cable must be 5 m or shorter. 
 
Remove the short-circuit bar only if you connect the DC reactor for use. 
If you remove the short-circuit bar with the DC reactor unconnected, the inverter cannot operate 
because no power is supplied to its main circuit.