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Installation_Guide_SIAB000B0010AA_Rev. 03 14 / 32
5.1. Test Winding
Unlike the standard current transformers that provide a nominal secondary current of 1A or 5A,
these specific current transformers have a very low current at their secondary.
SIA-B relay has been designed to work with these current levels. For this reason, it is not
possible to do the same tests that are performed with relays that use standard CTs.
The testing consists on the injection of 1A in test winding terminals, providing a simulated
primary current value, that will have a different primary value depending on the selected CT.
6. OPENING MECHANISM
The trip is associated to a striker. The type of trip is a polarized trip. There are a lot of models of
strikers in the market, with different trip energies, being for example 50 mJ (0,05W·s) and
operation voltage of 6V, or 135 mJ (0,1W·s) and operation voltage of 24V.
The opening mechanism is activated by means of a striker. The activation of the trip generates
a pulse train.
The
Trip Voltage Level
setting allows adjusting the trip voltage level required by the selected
striker. The default value is 17 Vdc, although there are several options:
•
12 Vdc
•
17 Vdc
•
22 Vdc
•
24 Vdc
The equipment will allow the trip when it gets the selected trip voltage, so if a lower level that
the required by the striker is adjusted, it may result on tripping without enough energy and not
activating the striker.
On the other hand, if a higher level that the required by the striker is selected, the activation of
the striker is guaranteed, however, the fault trip time during start-up may be increased. Fanox
encourages selecting the correct value of this critical setting and offers its expertise at any
doubt.
Striker
The striker is a bistable device with a simple action. The striker shaft is moved by a spring. The
striker is activated by a polarized low-power electrical signal, supplied by the relay if a fault
occurs. Resetting the shaft to its position is done manually. Resetting the striker has to be done
in such a way as to guarantee that the opening mechanism is closed. This is normally done
manually.
Due to the existing variety in the market, it is important to check the voltage and the necessary
energy for its activation.