Component Descriptions; Ac Reactors, Input Side - Omron 3G3MX2 User Manual

Component Descriptions

5-2 Component Descriptions
5-2-1

AC Reactors, Input Side

256
This is useful in suppressing harmonics induced on the power supply lines, or
when the main power voltage imbalance exceeds 3% (and power source
capacity is more than 500 kVA), or to smooth out line fluctuations. It also
improves the power factor.
In the following cases for a general-purpose inverter, a large peak current
flows on the main power supply side, and is able to destroy the inverter mod-
ule:
• If the unbalanced factor of the power supply is 3% or higher
• If the power supply capacity is at least 10 times greater than the inverter
capacity (the power supply capacity is 500 kVA or more)
• If abrupt power supply changes are expected
Examples of these situations include:
1. Several inverters are connected in parallel, sharing the same power bus
2. A thyristor converter and an inverter are connected in parallel, sharing the
same power bus
3. An installed phase-advance (power factor correction) capacitor opens and
closes
Where these conditions exist or when the connected equipment must be
highly reliable, you MUST install an input-side AC reactor of 3% (at a voltage
drop at rated current) with respect to the supply voltage on the power supply
side. Also, where the effects of an indirect lightning strike are possible, install
a lightning conductor.
Example calculation:
V = 205 V, V = 203 V, V
RS ST
where VRS is R-S line voltage, VST is S-T line voltage, VTR is T-R line volt-
age
Unbalance factor of voltage =
Max. line voltage (min.) − Mean Line voltage
Meanline voltage
(
−
V
RS
=
(
V
RS
Please refer to the documentation that comes with the AC reactor for installa-
tion instructions.
Fig. 1
= 197 V,
TR
×
100
)
+ +
V V V
RS ST TR
3
×
100
)
+ +
V V
ST TR
3
Section 5-2
−
205 202
= × =
100 . 1 5 %
202
Fig. 2