SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.

Chapter 6 Maintenance and Inspection
6.6 DC-Bus Capacitor Life Curve
Ambient temperature (ºC)
50
When energized 24 hours a day
40
30
20
10
0
-10
1 2 3 4 5 6 7 8 9 1
Capacitor life (number of years)
Note 1:
Note 2:
The ambient temperature indicates the temperature measured at a position about 5 cm distant
from the bottom center of the inverter body. If the inverter is mounted in an enclosure, the
ambient temperature is the temperature within the enclosure.
The DC-Bus capacitor has a limited life because chemical reactions occur inside the capacitor
during operation. You should replace the DC-Bus capacitor after about 10 years of use as
standard. (10 years is not the guaranteed lifespan but rather, the expected design lifespan.)
Note that the smoothing capacitor life will be shortened significantly if the inverter is used at a
high ambient temperature or with a heavy load that requires a current beyond its rated current.
6.7 Output of Life Warning
The inverter can output a warning based on self-diagnosis when the life of a life-limited part (smoothing
capacitor on the circuit board or cooling fan) (except the smoothing capacitor in the main circuit) in the
inverter is expiring. Use the life warning as an indication for the timing of part replacement.
For details, see Sections 4.1.19, "Life-check monitoring," (on page 4-5), 4.2.56, "Intelligent output terminal
setting," (on page 4-59), and 4.2.57, "Intelligent output terminal a/b (NO/NC) selection," (on page 4-60).
The self-diagnosis for the life warning is based on the expected design life (which is not the guaranteed
life) of each part. The actual parts life may vary depending on the inverter operation environment and
conditions.
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