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10.3. Operations before putting into service
Before putting the circuit-breaker into service, carry out the following operations:
– remove the lifting hooks;
– check tightness of the power connections at the circuit-breaker terminals;
– establish the setting of the primary electronic overcurrent release (if provided);
– check that the value of the power supply voltage of the auxiliary circuits is between 85% and
110% of the rated voltage of the electrical accessories;
– remove any remains of packing materials;
– check that no foreign bodies, such as bits of packing, have got into the moving parts;
– remount any covers removed during the testing operations;
– check that there is a sufficient exchange of air in the installation place to avoid overtemperatures;
– supply the auxiliary circuits with power;
– check the functionality and efficiency of the mechanical and electrical locks;
– carry out a few circuit-breaker opening and closing operations by means of the pushbuttons on
the front of the circuit-breaker;
– also carry out the checks indicated in table T3.
T3
ITEM INSPECTED
1
Insulation resistance.
2
Auxiliary circuits.
3
Auxiliary contacts in the drive.
4
Locking electromagnet on the
circuit-breaker truck (-RL2).
5
Auxiliary transmitted contacts
signalling circuit-breaker racked-in,
isolated (UniGear switchgear or
PowerCube modules).
PROCEDURE
Medium voltage circuit
With a 2500 V megger, measure the insulation resist-
ance between the phases and the exposed conductive
part of the circuit.
Auxiliary circuits
With a 500 V megger (if the apparatus installed allows
this), measure the insulation resistance between the
auxiliary circuits and the exposed conductive part.
N.B. Before carrying out the test, disconnect the earth-
ing of the electronic card from the circuit-breaker frame
and reconnect it after the test.
In particular, the communication connection must be
disconnected to the protection and control unit,
connector -XB24, and to the power supply connection
(protected by a 275V common mode varistor),
connector -XB24, both on the mother card of the
protection and control unit.If the communication
connection to the control and protection unit is made
using connector D-Sub 9-pin for DIN rail in a
secondary compartment, disconnect this connection.
Check that the connections to the control circuit are
correct: proceed with the relative power supply.
Insert the auxiliary contacts in suitable signalling cir-
cuits.
Carry out a few closing and opening operations
With the circuit-breaker open, in the isolated for test
position and the locking electromagnet not supplied,
attempt to rack in the circuit-breaker.
Supply the locking electromagnet and carry out the
racking-in operation.
Insert the auxiliary contacts in suitable signalling
circuits.With the circuit-breaker racked into the enclo-
sure, carry out a few traversing operations from the
isolated for test position to the racked-in position.
Take the circuit-breaker to the racked-out position.
POSITIVE CHECK
The insulation resistance should be at least 50 Mohm
and in any case constant over time.
The insulation resistance should be a few Mohm and
in any case constant over time.
Operations and signals are normal.
The signals take place normally.
Racking-in is not possible.
Racking-in takes place correctly.
The signals due to the relative operations take place
regularly.
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