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The switching units with command of 12v DC latching can be commanded either by three wired
command or two wired command.
All types of switching units act like a relay that when activated they let the power through and
when deactivated they cut off the power from the load. In any case, the power to be switched
comes from external source and not generated internally by the unit.
When the load is a 3- phase load or it is too big, then the pump-switching unit will not switch
the power to the pump directly, but rather activate a contactor that will switch the pump ON
and OFF.
IMPORTANT:
1. In each package of PUMP SWITCHING UNIT a capacitor of 1 µF 400v is supplied. this capacitor
should be installed in parallel with the load, otherwise in some cases the pump will not turn
OFF.
2. The internal contact of the solid state relay cannot be tested by Ohm-meter.
The 12v DC
power to be
connected here
The command
from controller
arrives here
The power to
be switched
enters here
The power to
the load exits
from here
No need for
12v DC power