Omron RX2 Series User Manual page 104

2 Design
 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.
 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 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 side
of the inverter.
 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.
Wire the inverter so that the heat from DC reactor (DCL) does not give any influences on the
inverter.
Before connecting the DC reactor DCL option, remove this short-circuit bar between PD and P.
Note that the length of the DC reactor connection cable must be 5 m or shorter. Otherwise, you can-
not have enough results you desire.
In case you do not use DC reactor DCL option, do NOT remove the PD-P short bar.
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.
2 - 50
Voltage
Voltage
Voltage
Current
Current flows only during the charging of a
capacitor. The waveforms of current differs from
voltage.
High-function General-purpose Inverter RX2 Series User's Manual
Time
Conversion with a
rectifier
Time
Smoothing with a
capacitor
Time
Time