11.4 Option
11-47
Chapter 11 SELECTING PERIPHERAL EQUIPMENT
[3] DC reactor (DCR)
A DCR is mainly used for power supply matching and for input power factor correction (for reducing
harmonic components).
îš„ For power supply matching
• 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 percent reactance of the power supply decreases, and
harmonic components and their peak value increase. These factors may break rectifiers or main circuit
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 phase-advancing capacitors are being
turned ON/OFF at the same power supply.
• Use a DCR when the interphase voltage unbalance ratio of the inverter power supply exceeds 2%.
67
(V) voltage average phase-Three
(V) voltage Min. - (V) voltage Max.
= (%) unbalance voltage Interphase ×
îš„ Input power factor correction (for reducing harmonic components)
Generally a capacitor is used to improve 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 supply so as to
decrease harmonic components on the power supply lines and improve the power factor of inverter. Using
a DCR improves the input power factor to approximately 86% to 95%.
• At the time of shipping, a jumper bar is connected across terminals P1 and P (+). Remove
the jumper bar when connecting a DCR.
• If a DCR is not going to be used, do not remove the jumper bar.
Figure 11.4-17 External View of a DC Reactor (DCR) and Connection Example
To Next Page
Loading...
Need help?
General
