F&F PF-431-LED TRMS Instruction Manual page 2

Functioning
A three-phase voltage is applied at the input of the switch.
Voltage of one of the phases is applied at the output of the
switch.
The electronic system of the switch controls RMS values of the
applied phase voltages so that the output voltage is not lower
than 190 V or higher than 280 V. Phase with the correct parame-
ters is directed at the output of the switch. The corresponding
LED light indicates that the indicated phase is connected to the
output of the switch. L1 phase is the priority phase, i.e. that if
its parameters are correct, this phase will be always switched
to the output.
If a voltage in L1 phase would drop below 190 V, its loss or in-
crease above 280 V (the green L1 LED goes off), the electronic
system will switch phase L2 to the output (if its parameters are
correct).
In the case of a simultaneous lack of correct voltages in L1 and
L2 phases (L1 and L2 green LEDs go off), the L3 phase will be
switched to the output.
When the correct supply voltage returns to the L1 phase (voltage
in the range 190÷280 V), the system switches this phase to the
output. After connecting the supply voltage the system blinks
once with all LEDs, which indicates the appearance of voltage
on the device (but not on the output). Then the device analyzes
the network parameters and switches to the appropriate phase
output. If the power supply N wire is connected to the wrong
place, instead of switching one of the phases to the output, the
device will signal an incorrect connection by lighting the LEDs in
the order L1, L2, L3 („passing" diode). In this case, disconnect
the power supply from the device and connect the input wires
correctly.
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