3UG4.1 line monitoring relay
6.5 3UG4614 line monitoring relay
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
133
The output relays respond in accordance with the set relay switching behavior (closed-circuit
principle NC or open-circuit principle NO) if the following conditions are met:
● Correct phase sequence at terminals L1-L2-L3
● The monitored voltage (Ux-y) is larger than the set value
● The voltage symmetry (Asy) is smaller than the set value
If a fault occurs (phase failure, incorrect phase sequence, or phase asymmetry), the output
relays switch in accordance with the relay switching behavior.
In the case of incorrect direction of rotation, the 3UG4614 line monitoring relays immediately
shut down. 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 80 % from the
load in the case of regenerative power recovery.
On failure of one of the phases, the output relays drop out immediately to protect the
application from any damage that may result. Set delay times have no effect on the phase
failure monitoring.
Note
The 3UG4614 line monitoring relays are only suitable for line frequencies of 50
/ 60 Hz!
After applying the supply voltage or resetting the monitoring relays, the set ON-delay begins
(onDel). During this time, undershooting or overshooting of the set threshold values will not
cause the CO contact to respond but instead will result in a restart of the ON-delay.
If the measured value overshoots or undershoots the set threshold after expiry of the ON-
delay time (onDel), the set tripping delay time (Del) and the relay symbol will flash. After
expiry of this time, the output relays change the switching state. On the display, the current
measuring value and the symbol for undershoot or overshoot flash.
You will find the switching states of the output relays below in section "Function diagrams"
and in Chapter "Diagnostics (Page 136)."
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