7.2 Tests during inspections and after tripping
The following tests must be conducted during inspection, after tripping, and after lengthy
storage under certain environmental conditions before re-commissioning. These can be
performed with a TD310 test device to power the ETU. They are not absolutely necessary after
delivery from the factory because the devices are 100% tested before shipment. A trip test
conrms correct mechanical functioning of the tripping plunger on the trip coil, actuated by the
ETU. Electronic monitoring of the entire connection between the current transformers, ETU, and
trip coil is performed continuously by the electronics itself (watchdog).
Items to be tested Checks
Enable alarms Connect the ETU to a test device and check that no alarms are present.
Status of the circuit
breaker
On the ETUs of the 3-series, the status of the circuit breaker must not be
incorrect (see tables of the LED display in Chapter Alarms (Page191)).
Perform a close/open operation on the circuit breaker and check that no
alarms have occurred.
On the ETUs of the 6-series, the status of the circuit breaker must be
correctly shown on the display. Perform a close/open operation on the
circuit breaker and check that the change in circuit breaker status is cor‐
rectly displayed.
Trip test Make a trip attempt with the circuit breaker closed during an idle period
(without circulating currents of the mains connection) and check that
the circuit breaker opens.
7.3 Maintenance intervals
Environment with standard conditions
Following initial commissioning, the equipment/system must be serviced at least once per
year or after 2000switching operations.
Note
These maintenance intervals also apply to circuit breakers that are used irregularly or that
remain in the same switch position for long periods.
Dusty environment
If the circuit breaker is operated in a dusty environment (dust component >1mg/m
3
), it
should be maintained at least twice a year or after 1000switching operations.
Service and maintenance
7.3Maintenance intervals
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
200 Equipment Manual, 10/2023, L1V30499596002-03
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