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The MIF relay works with 'wet contacts'. A wet contact has one side connected to the positive terminal of an external
DC power supply. The other side of this contact is connected to the required contact input terminal (A8 or A9). In
addition, the negative side of the external source must be connected to the relay common (negative) terminal (A10).
The maximum external voltage source voltage for this arrangement is 300 Vdc.
The voltage threshold at which an input will detect a closed contact input depends on the relay model. For low voltage
range relays (F model), the threshold is set to 12 Vdc. For high voltage range relays (H model), the voltage threshold
is 75 Vdc.
In case of using AC voltage, it must be ensured that there is no appreciable voltage (less than 10 Vac) between the
input common terminal, A10, and the ground terminal. The AC system must be line/neutral type, and not line/line,
ensuring that the neutral and ground do not differ in more than 10 Vac. The reason for this is that there might be
enough current circulating through the EMC filtering capacitors on these inputs to cause undesired activation.
If it is not possible to ensure the previous conditions, the connection shown below can be used, where lines are wired
only to inputs (A8 and A9), and the common (A10) is connected to the unit ground terminal.
3-30
PRODUCT DESCRIPTION
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AUXILIARY
VOLTAGE
VDC or VAC
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Figure 3-7 CONTACT INPUTS CONNECTIONS
MIF Digital Feeder Protection
3.2.4.
G E P o w e r M an ag em e n t
MIF
A8
CC1
A9
CC2
A10
COM
CONTACT INPUTS / OUTPUTS
GEK-106273L
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