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Inrush current flow when the inverter power supply is turned ON
When the inverter power supply is turned ON, the charging current, which is called inrush current,
flows in the main circuit board capacitor.
The table below shows the reference values at a power supply voltage of 200 V or 400 V when the
power supply impedance is low. Take this into consideration when selecting the inverter power sup-
ply.
•
With a low-speed no-fuse breaker, an inrush current 10 times the rated current can flow for 20 ms.
•
To turn ON the power supply for multiple inverters simultaneously, select a no-fuse breaker whose
20-ms allowable current rating is greater than the total inrush current of the inverters.
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Main power supply phase loss and single-phase input
To use a single-phase power supply, use a single-phase 200-V class inverter.
Using a single-phase power supply to supply power to a 3-phase 200-V or 3-phase 400-V class
inverter may cause damage to the inverter.
The inverter may also be damaged if phase loss occurs in the main power supply, because it does
not have any function to detect main power supply phase loss.
Be sure to check that the 3-phase power supply is wired properly before using the inverter.
Even when the inverter is in an input phase lost state, built-in capacitors are charged, which
may result in an electric shock or injury.
Be sure to check the precautions provided in Precautions for Safe Use on page 2-4.
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Power supply environment
In the following cases, the internal converter module (rectifier) may be damaged.
Take countermeasures such as installing an AC reactor on the main circuit input side of the inverter.
•
The power supply voltage unbalance factor is 3% or more.
•
The power supply capacity is at least 10 times larger than the inverter capacity and, at the same
time, 500 kVA or more.
•
Rapid change in the power supply voltage occurs.
Example. When the phase advance capacitor is turned on/off, the inverter may detect an overvolt-
age or the rectifier may be damaged.
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Installing input surge absorber
When using an inductive load (such as a magnetic contactor, magnetic relay, magnetic valve, sole-
noid, or electromagnetic brake), use a surge absorber or diode together.
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