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DMX
3
- Disconnect all the device electric accessories
from the auxiliary circuit
• To successfully complete all the dielectric
checks, set back the button in working position
and connect all the accessories
• To verify the presence and value of the
voltage up-stream and down-stream the device
How to resume the device after
tripping
In case during the functioning the breaker trips,
the assigned personnel must respect the following
procedure:
• To indentify the reason of the release and if it is
related to a protection event or an external circuit
• To check the protection unit history log (see the
protection unit user manual).
• To verify the position of MAN/AUT button. If it is
in MAN position after the protection unit tripping,
the RESET button is released and, to assure more
safety, it’s impossible to close the breaker. In this
case the personnel must understand the reason
of the fault and set back the RESET button before
start working again.
• If the button is in AUT position the device is able
to close even after a protection tripping, without
any on site intervention of personnel, allowing
the closing by remote if needed by the system
manager. In this case an automatic and remote
system is needed.
Identification of the fault
The fault is shown locally on the protection unit and/
or by the auxiliary contacts installed on the device.
In case of fault it is strongly suggested to inspect the
device (see Maintenance guide)
Reasons fault
The device shouldn’t be closed again before chec-
king and solving the cause of the fault (locally or by
remote).
The reasons may be various:
the reasons may be classified in two main types
• fault protection (see the hystory log of the protec-
tion unit)
• ST and UVR intervention
After checking the reason of the fault, before closing
the device again, it’s suggested to check the device
conditions, and above all, to check the dielectric and
insulation conditions of one part or the whole device
depending on the nature of the tripping event.
Those checks and tests must be requested and
managed by qualified personnel according to this
user manual.
In case of short circuit,
device inspection
In case of short circuit protection, go to Maintenance
guide and check the following conditions:
• to check the arc chamber conditions and the wear
status
• to check the contacts status
• to check the clamping of the power connections
and the auxiliary circuit connections as shown in
the Start UP chapter
• in case of draw-out version device, take out the
breaker and check the insertion clamps and the
inside conditions
Device closing
The closing of the breaker can be performed locally
or by remote only after checking that the system and
the device conditions are consistant with the safety
procedure.
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