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Maintenance and Inspection
Troubleshooting
and Maintenance
6–12
Spare parts We recommend that you stock spare parts to reduce down time, including parts listed below:
Capacitor
Life Curve
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 smooths the power for use by the inverter. So,
any degradation of the capacitor will affect the performance of the inverter. The capacitor bank
in SJ300 series inverters is replaceable. This section will show you how to replace it in the field.
Capacitor life is reduced in higher ambient temperatures, as the graph below demonstrates. 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.
Part description Symbol
Quantity
Notes
Used Spare
Cooling fan FAN 1, 2, 3... (depends
on model)
1 or 2 Fan unit at top of housing
in all models
Auxiliary cooling fan FAN 0 or 1... (depends
on model)
0 or 1 –150Lxx, –185Lxx, and
–220Lxx models
Capacitor bank CB 1 1 All models
Power
Input
Inverter
L1/R
Motor
L2/S
L3/T
Rectifier
Variable-frequency Drive
Internal DC Bus
+
+
–
U/T1
V/T2
W/T3
Converter
Ambient
temperature, °C
Ye a r s
Capacitor Life Curve
12 hrs / day operation
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0
20
40
30
50