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L100 Inverter
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CAUTION: SUPPRESSION FOR NOISE INTERFERENCE FROM INVERTER
The inverter uses many semiconductor switching elements such as transistors and
IGBTs. Thus, a radio receiver or measuring instrument located near the inverter is
susceptible to noise interference.
To protect the instruments from erroneous operation due to noise interference, they
should be used well away from the inverter. It is also effective to shield the whole
inverter structure.
The addition of an EMI filter on the input side of the inverter also reduces the effect of
noise from the commercial power line on external devices.
Note that the external dispersion of noise from the power line can be minimized by
connecting an EMI filter on the primary side of inverter.
CAUTION: EFFECTS OF POWER DISTRIBUTION SYSTEM ON INVERTER
In the cases below involving a general-purpose inverter, a large peak current can flow on
the power supply side, sometimes destroying the converter module:
1. The unbalance factor of the power supply is 3% or higher.
2. The power supply capacity is at least 10 times greater than the inverter capacity (or
the power supply capacity is 500 kVA or more).
3. Abrupt power supply changes are expected, due to conditions such as:
a. Several inverters are interconnected with a short bus.
b. A thyristor converter and an inverter are interconnected with a short bus.
c. An installed phase advance 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.
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EMI Filter Inverter
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EMI Filter
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Completely ground the
enclosed panel, metal
screen, etc. with as
short a wire as possible.
Grounded frame
Conduit or shielded
cable—to be grounded