Siemens SIRIUS 3RT Series - Configuration; Current Monitoring Relay Application Areas; Fault Detection

SIRIUS 3RR2 current monitoring relays
8.5 Configuration
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
695
8.5 Configuration
8.5.1 Current monitoring relay application areas
The 3RR2 current monitoring relay can be used for both system and machine protection. If
parameterizable current values are overshot or undershot, the current monitoring relay
switches after an adjustable delay has elapsed.
The current monitoring relay detects electrical changes immediately. It will even respond to
minor, insidious changes, and is also capable of underload monitoring.
The current monitoring relay will protect the system in the following situations:
● Overload
● Underload
● Phase failure/wire break
● Load surges
● Wear
● Long starting/heavy-duty starting
● Blocked rotor (3RR22)
● Fault current/ground fault (3RR22)
● Incorrect phase sequence (3RR22)
8.5.2 Fault detection
The current monitoring relay detects faults and blockages on the basis of changes in current.
Example applications:
● Detection of blocked filters, e.g. on fans and pumps
● Detection of pumps working against a closed slide valve
● Detection of machine blockages during operation (e.g. chip conveyors, pumps, crushers,
gear breakage)
● Faster blocking detection than with I²t characteristic curve, particularly with
overdimensioned motors
● Protection against mechanical system damage in the event of load surges as "electronic
shear pin"