L6555
Emax
31/74
Doc. No
Model
Apparatus
Scale
Page No
1SDH000460R0002
Auxiliary contacts
Auxiliary contacts installed on the circuit-breaker are available to enable an indication of the circuit-breaker’s status. A special
version of the auxiliary contacts is also available (gold plated contacts) for a rated voltage under 24 V (digital signal).
Un In max T
125 V DC 0,3 A 10 ms
250 V DC 0,15 A 10 ms
Un In max cosφ
250 V AC 5 A 0,3
The versions available are:
a) Electrical signalling for circuit-breaker open/closed
It is possible to have electrical signalling of the circuit-breaker status (open/closed) 4, 10 or 15 auxiliary contacts.
The auxiliary contacts can have the following confi gurations:
- 4 break/make contacts for PR121 (2 normally open + 2 normally closed)
- 4 + 2 break/make contacts for PR122/ PR123 (2 normally open + 2 normally closed + 2 for the release)
- 10 break/make contacts for PR121 (5 normally open + 5 normally closed);
- 10 + 2 break/make contacts for PR122/ PR123 (5 normally open + 5 normally closed + 2 for the release)
- 15 supplementary break/make contacts which can be mounted outside the circuit-breake
The basic confi guration described above can be modifi ed by the user to indicate normally open or normally closed by reposition-
ing the faston connector on the microswitch. When 10 contacts for PR122/ PR123 are required, zone selectivity and the PR120/K
module are not available.
Reference Fig. in the electrical circuit diagrams: Q/1÷10 (21-22)
b) Electrical signalling for circuit-breaker connected/test isolated/disconnected
In addition to mechanical signalling of the position of the circuit-breaker, it is possible to have electrical signalling by means of 5
or 10 auxiliary contacts which are installed on the fi xed part.
Only available for circuit-breakers in withdrawable versions for installing on the fi xed part.
The auxiliary contacts can have the following confi gurations:
- 5 contacts; group consisting of 2 connected signalling contacts, 2 disconnected signalling contacts and 1 test position signal-
ling contact (main contacts isolated, but sliding contacts connected)
- 10 contacts; group consisting of 4 connected signalling contacts, 4 disconnected signalling contacts and 2 test position signal-
ling contacts (main contacts isolated, but sliding contacts connected)
Reference fi gure in the electrical circuit diagrams: S75I (31-32) - S75T (31-32) - S75E (31-32)
c) Contact for signalling closing springs loaded
This consists of a microswitch which allows remote signalling of the state of the circuit-breaker operating mechanism closing
springs. The contact is always supplied with the spring loading geared motor.
Reference fi gure in the electrical circuit diagrams: S33 M/2 - (11)
d) Contact for signalling undervoltage release energized (C.aux YU)
The undervoltage releases can be fi tted with a contact (by choise, normally closed or open) for signalling undervoltage energized
for remote signalling of the state of the undervoltage release.
Reference fi gure in the electrical circuit diagrams: (12)
Transformers and operation counters
a) Current sensor for the neutral conductor outside the circuit-breaker
The sensor allows neutral protection by means of connection to the overcurrent release and is available only for three-pole circuit-
breakers. It is supplied on request.
Reference fi gure in the electrical circuit diagrams: UI/N
b) Homopolar toroid for the power supply earthing conductor (star center of the transformer)
PR122 and PR123 microprocessor-based electronic releases may be used in combination with an external toroid located on
the conductor, which connects the star center of the MV/LV transformer (homopolar transformer) to earth: in this case, the earth
protection is defi ned as Source Ground Return.
The In of the toroid can be regulated to 100 A, 250 A, 400 A, 800 A by using different combinations of the connections.
Reference fi gure in the electrical circuit diagrams: UI/0.
c) Homopolar toroid for residual current protection
The toroid enables the residual current protection to be activated and can be combined with the PR122/P LSIRc, PR122/P LSIG
releases (with PR120/V) and PR123/P. The accessory is for installation on the busbars and is available in different sizes: up to
3200A for three- and four-pole circuit-breakers, up to 4000A for three-pole circuit-breakers.
d) Mechanical operations counter
This is connected to the operating mechanism by means of a simple lever mechanism. It indicates the number of circuit-breaker
mechanical operations. The indication is visible on the front of the circuit-breaker from the outside.
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