Maintenance and Inspection
8-
3
Periodic Inspection
Check the following items during periodic inspections.
Turn off the power supply, make sure that all LEDs on the front cover of the cell control board are unlit, and
then wait at least 5 minutes (10 minutes after turning off a medium voltage power supply) before starting
inspection.
Touching terminals immediately after turning off the power supply may result in electric shock.
Table 8.2 Periodic Inspections (Once per Year)
Location
Item
Inspection
Transformer
Panel,
Power Cell
Panel
Entire Transformer
and Power Cell
Panels
Megger check between the main circuit terminals and ground terminal
Check for loose screws, bolts, or connectors.
Check for trace of overheat on each part.
Clean inside the panels.
Wires
Check for damage or deterioration of cable sheath.
Transformer
Confirm primary/secondary voltages are normal.
Power cells
Check for leakage from the smoothing capacitor.
Confirm the safety valve of the smoothing capacitor is not protruding.
Confirm the smoothing capacitor has not expanded.
Measure the capacitance of the smoothing capacitor.
Check for loose screws or bolts.
Confirm if the main circuit and control circuit fuses are normal.
Check for accumulated dust and dirt on the heat sink.
Control Panel
Operation
Confirm no abnormalities in protective and indication circuits
Relays
Confirm smooth operation
Confirm timer operation.
Check for damaged contacts.
Board
Check for abnormal smells and discoloration.
Confirm the power supply voltage.
Cooling system Cooling fan
Check for abnormal vibration and noise.
Confirm the bearing operation.
