Siemens SIRIUS 3UG4 Equipment Manual page 88

3UG4.1 line monitoring relay
6.3 3UG4512 line monitoring relay
All 3UG4512 line monitoring relays feature at least one output relay (output relay K1 CO
contact). The 3UG4512-.B line monitoring relays have an additional relay (output relay K2 CO
contact). Output relay K2 switches synchronously with output relay K1.
No settings are required for operation.
Note
The specified voltages represent the absolute thresholds.
Monitoring
Thanks to a special measuring method, a phase failure is detected with certainty despite wide-
range voltage from 160 to 690 V AC and reverse power of up to 90 % from the load in the case
of regenerative power recovery.
If the line voltage is switched on, the LED "coil symbol" will light up green. If the correct phase
sequence is applied to terminals L1‑L2‑L3, the output relays pick up. If the phase sequence is
incorrect, the "phase failure / phase sequence" LED flashes red and the output relays remain in
their quiescent position. On a phase failure, the "phase failure / phase sequence" LED lights up
red continuously and the output relays drop out to protect the application from any damage that
may result.
You will find the switching states of the output relays below in section "Function diagrams" and
in Chapter "Diagnostics (Page 89)."
Reset response
The device features an autoreset function. The autoreset function resets the output relay to its
original state after an error message and rectification of the fault that has occurred.
Note
The red "phase failure / phase sequence" LED is a fault diagnostics display and does not indicate
the current state of the relay!
88
SIRIUS 3UG4 / 3RR2 monitoring relay
Equipment Manual, 07/2021, NEB927043002000/RS-AD/005