Monitoring Functions - Siemens SIRIUS 3RT Series System Manual

SIRIUS 3RR2 current monitoring relays
8.10 Technical data
8.10.1.2

Monitoring functions

Table 8- 15 Monitoring functions of 3RR2 current monitoring relays
Feature
Current overshoot
Current undershoot
Apparent current monitoring
Active current monitoring
Range monitoring
Phase failure, wire break
Phase sequence error
Internal ground-fault
detection (fault current
monitoring)
Blocking current monitoring
734
Benefit
Provides optimum current-dependent

protection of loads against impermissibly high
temperature rise due to overload
Enables detection of filter blockages or pumps

working against closed slide valves
Enables conclusions to be drawn about wear,

poor lubrication or other phenomena relevant
to maintenance
Enables detection of overload due to a slipping

or torn belt
Ensures that pumps are protected against

running dry
Straightforward function monitoring of resistive

loads such as heaters
Permits energy savings to be made through

monitoring of no-load operation
Sensitive current monitoring specifically in a

motor's rated and upper torque range
Optimum current monitoring over a motor's

entire torque range thanks to the patented
combination of power factor and apparent
current monitoring
Simultaneous monitoring for current overshoot

and undershoot with a single device
Minimizes the temperature rise of the three-

phase motor in the event of a phase failure
thanks to immediate disconnection
Prevents hoisting gear from operating with half

payload
Prevents motors, pumps or compressors

starting up in the wrong direction of rotation
Provides optimum protection of loads in the

event of high-impedance faults to ground
caused by moisture, condensation, damaged
insulation, etc.
Eliminates the need for additional special

equipemnt
Saves space in the control cabinet

Reduces wiring outlay and costs

Prevents temperature rise of the three-phase

motor in the event of blocking during operation
thanks to direct disconnection
Minimizes the mechanical loading of the

system by functioning as an electronic shear
pin
3RR21 Basic, 3RR22 Standard,
analog setting digital setting
✓ (2-phase)
✓ (2-phase)
✓
- ✓ (selectable)
✓ (2-phase)
✓ (2-phase)
- ✓ (selectable)
- ✓ (selectable)
- ✓ (selectable)
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
✓ (3-phase)
✓ (3-phase)
✓
✓ (3-phase)
✓ (3-phase)