Hitachi WJ200-001S Instruction Manual page 326

Capacitor Life Curves
The DC bus inside the inverter uses a large capacitor as shown in the diagram below.
The capacitor handles high voltage and current as it smoothes the power for use by the
inverter. So, any degradation of the capacitor will affect the performance of the
inverter.
Power
Input
Converter
R/L1
S/L2
T/L3
Capacitor life is reduced in higher ambient temperatures, as the graph below
demonstrates. Under the condition of average ambient temperature 40degC, 80% load,
24 hours operation, the lifetime is 10years. Be sure to keep the ambient temperature at
acceptable levels, and perform maintenance inspections on the fan, heat sink, and
other components. If the inverter is installed on a cabinet, the ambient temperature is
the temperature inside the cabinet.
50
Ambient
temperature, C
40
30
20
10
Variable-frequency Drive
Internal
DC Bus
Rectifier
Capacitor Life Curve
0 1 2 3 4
Inverter
Operation 24hours/day, 80% load
Operation 24hours/day, 100% load
5 6 7 8 9
621
Motor
U/T1
V/T2
W/T3
Years
10