
3RR2 current monitoring relays
4.1 Product description
3UG4 / 3RR2 monitoring relays
46
Manual, 05/2016, NEB927043002000/RS-AC/004
System integration
3RR2 current monitoring relays are available in three sizes, S00, S0 and S2. 3RR2 current
monitoring relays are matched to 3RT2 contactors and 3RF34 (size S0) solid-state
contactors in terms of their electrical and mechanical features. They can be integrated in the
feeder by means of direct mounting. This eliminates the need for the main circuit to be wired
separately and no additional transformers are required.
For a stand-alone assembly or if an overload relay is being used at the same time, terminal
supports for stand-alone assembly are available for separate DIN rail mounting.
3RR2 current monitoring relays were conceived for monitoring 3-phase systems.
Depending on the device version used, monitoring of 1- or 2-phase AC systems is possible
with the following wiring variants:
①
Complete device functionality possible
②
Device functionality only possible with limitations:
•
Residual current monitoring not possible (→ switch off)
•
Phase sequence monitoring not possible (→ switch off)
•
Active current monitoring not possible (→ switch off)
Note
The monitoring functions of the 2 phases (3RR21) or the 3 phases (3RR22) are ORed to the
output relay(s), i.e. a fault in one monitored phase (e.g. current violation L1) already affects
the output relay(s).
Accessories
The accessories have been tailored to the current monitoring relays; they can be mounted
easily and without the need for tools. The accessories are described in the Chapter
"Accessories for 3RR2 current monitoring relays (Page 323)".