Fuji Electric frenic mini series, User Manual

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6.4 Selecting Options
6-15
Chap. 6
SEL
ECT
ING P
E
R
IP
HE
RAL
EQ
UIPM
ENT
[ 2 ] DC Reactors (DCRs)
A DCR is mainly used for power supply normalization and for supplied power factor reformation
(for reducing harmonic components).
■ For power supply normalization
- Use a DCR when the capacity of a power supply transformer exceeds 500 kVA and is 10 times or
more the rated inverter capacity. In this case, the percentage-reactance of the power source
decreases, and harmonic components and their peak levels increase. These factors may break
rectifiers or capacitors in the converter section of inverter, or decrease the capacitance of the
capacitor (which can shorten the inverter's service life).
- Also use a DCR when there are thyristor-driven loads or when condensive capacitors are being
turned on/off.
- Use a DCR when the interphase voltage unbalance ratio of the inverter power source exceeds
2%.
67
V) ( voltage average phase - 3
V) ( voltage Min. V) ( voltage Max.
= %) ( unbalance voltage Interphase
×
−
■ For supplied power factor reformation (harmonic component reduction)
Generally a capacitor is used to reform the power factor of the load, however, it cannot be used in a
system that includes an inverter. Using a DCR increases the reactance of inverter's power source so
as to decrease harmonic components on the power source lines and reform the power factor of
inverter. Using a DCR reforms the input power factor to approximately 95%.
•
At the time of shipping, a short bar is connected across terminals P1 and P (+) on the
terminal block. Remove the jumper bar when connecting a DCR.
• If a DCR is not going to be used, do not remove the jumper bar.
Figure 6.9 External View of a DC Reactor (DCR) and Connection Example