INSPECTION AND MAINTENANCE
78 / 146 OI 250 (EN) REV7 /REV3
9.3 Maintenance
The circuit breaker must be shut down for maintenance work.
Opening the pole columns is not necessary.
• Disconnect the breaker from the high voltage system, and ground
(earth) the breaker at both ends.
• Discharge the closing and opening springs.
This state is reached when the position indicator shows OPEN
and the spring position indicator is on "discharged." The
operations shown in the table below are required to reach this
state, depending on the starting situation:
9.3.1 Checking the Cable Connections
• Check to make sure all cable connections in the mechanism
housing are tight.
9.3.2 Checking the Connecting Linkage
• Check all the fastening and locking elements (pins, nuts, screws
and bolts) on the connecting linkage.
9.3.3 Checking the Control Circuits
• Carry out test operations in accordance with the commissioning
procedure (see “Test Operations” on Page 59).
Breaker Position State of the
Closing Spring
Operations to Be
Executed
CLOSED / I Charged O-C-O
CLOSED / I Discharged O
OPEN / 0 Charged C-O
OPEN / 0 Discharged No operation requi-
red
Danger due to electric shock.
Therefore:
- Disconnect the breaker from the high voltage system and
ground (earth) the breaker at both ends.
Danger due to suddenly moving linkage.
Therefore:
- Discharge the closing and opening springs by carrying
out closing and opening operations.
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