3UG4625 residual current monitoring relay with 3UL23 transformer
8.3 Functions
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
197
Monitoring
Initialization
When the monitoring relay is connected to the supply voltage, the initialization phase starts
and internal functional tests are performed. During the initialization phase that lasts
approximately 1.6 s, the connection to the 3UL23 residual-current transformer is one of the
things that is checked. During this time, no measurement or monitoring of the fault current
takes place. - - A is shown on the display. The relay switching behavior during the
initialization phase can be determined with the help of the "Init" parameter. In the factory
setting ("Init" parameter = ERR), the output relays switch to the fault state until completion of
the initialization phase because there is no valid measuring result of the fault current.
If the parameter is set to "OK", it is assumed that there is no internal fault and the fault
current will be within the set limits. For this reason, the output relays are switched to the work
position when the supply voltage is present.
This parameter setting is useful if the residual current monitoring relays are not permanently
connected to the supply voltage and instead are to be started immediately when the
monitored application is started, and output relays in the alarm position result in immediate
shutdown of the application again, e.g. when connecting a contactor with interruption of the
self-locking by the output relay contacts.
After completion of the initialization phase, a permanent self-test takes place without
interrupting the monitoring function.
Normal operation
If the measured fault current exceeds the set warning threshold (I!), the associated CO
contact 21-22-24 changes the switching state without delay. On the display, the arrows for
"threshold overshot" and "measured value within the set limits" (
) flash alternately as an
indication.
On the display, the currently displayed measuring value and the symbol for overshoot flash.
Note
Currents with line frequencies of between 16 and 400 Hz can be monitored by 3UG4625
residual current monitoring relays in conjunction with 3UL23 residual current transformers!
Startup delay
The set ON-delay time is triggered if the fault current overshoots the lower measuring range
limit of 20 mA (onDel). During this time, exceeding the set limit values will not trigger a relay
response of the CO contacts.
To start a drive, the output relay switches to the correct state during the ON-delay time
(onDel), depending on the selected open-circuit principle or closed-circuit principle, even if
the measured value remains above the set value.
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 203)."
