User Manual

3UG4625 residual current monitoring relay with 3UL23 transformer
9.3 Functions
3UG4 / 3RR2 monitoring relays
Manual, 02/2013, NEB927043002000/RS-AA/002
193
Tripping delay
If the measured value exceeds the set threshold (I
▲
) after expiry of the ON-delay time
(onDel), the set tripping delay time (I
▲
Del) starts and the relay symbol flashes. After expiry of
this time, the output relay K1 changes the switching state. Exceeding the set warning
threshold will cause output relay K2 to switch immediately without taking into account the
tripping delay time. On the display, the actual measured value and the symbol for overshoot
flash.
You will find the switching states of the output relays below in section "Function diagrams"
and in Chapter "Diagnostics (Page 197)."
Tripping conditions
The combination of 3UG4625 residual current monitoring relay and 3UL23 residual current
transformer responds according to the following tripping conditions:
Residual current monitoring relays Fault current
No tripping 0 to 85 % of the set threshold
Tripping not defined 85 to 100 % of the set threshold
Tripping >= 100 % of the set threshold
3UL23 residual current transformer
3UL23 residual current transformers can be used in conjunction with 3UG4625 residual
current monitoring relays to detect fault currents in machines and systems.
3UL23 residual current transformers are suitable for detecting pure AC fault currents and AC
fault currents with a pulsating direct-current component.
These necessary accessories are described in Chapter "3UL23 residual current transformers
for 3UG4625 monitoring relays (Page 321)."
Note
Do not ground the neutral conductor downstream of the residual current transformer as
otherwise fault current monitoring functions can no longer be ensured.