Spare Parts; Capacitor Life Curve; Variable-Frequency Drive - Hitachi SJ300 Series Instruction Manual

6–12
Maintenance and Inspection

Spare parts

Capacitor
Life Curve
Power
Input
We recommend that you stock spare parts to reduce down time, including parts listed below:
Part description
Cooling fan
Auxiliary cooling fan
Capacitor bank
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.

Variable-frequency Drive

Converter Internal DC Bus
L1/R
L2/S
Rectifier
L3/T
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.
Ambient
temperature, °C
Quantity
Symbol
Used
FAN 1, 2, 3... (depends
on model)
FAN 0 or 1... (depends
on model)
CB 1
Inverter
+
+
–

Capacitor Life Curve

50
40
30
20
0
1 2 3 4 5
Notes
Spare
1 or 2 Fan unit at top of housing
in all models
0 or 1 –150Lxx, –185Lxx, and
–220Lxx models
1 All models
Motor
U/T1
V/T2
W/T3
12 hrs / day operation
6 7 8 9 10
Years