SIEMENS
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Siemens IC 10 · 2017
Relays
SIRIUS 3RR21, 3RR22 Monitoring Relays for Mounting onto 3RT2 Contactors
Current and active current monitoring
10
✓
Available
--
Not available
Monitoring functions
Current overshoot
✓
(Two-phase)
✓
(Three-phase)
• Provides optimum inverse-time delayed protection
of loads against excessive temperature rises due to
overload
• Enables detection of filter blockages or pumping
against closed gate valves
• Enables drawing conclusions about wear, poor
lubrication or other maintenance-relevant phenomena
Current undershoot
✓
(Two-phase)
✓
(Three-phase)
• Enables detection of overload due to a slipping or torn
belt
• Guarantees protection of pumps against dry running
• Facilitates monitoring of the functions of resistive loads
such as heaters
• Permits energy savings through monitoring of no-load
operation
Apparent current monitoring
✓
✓
(Selectable)
• Precision current monitoring especially in a motor's
rated and upper torque range
Active current monitoring
--
✓
(Selectable)
• Optimum current monitoring over a motor's entire
torque range through the patented combination of
power factor and apparent current monitoring
Range monitoring
✓
(Two-phase)
✓
(Three-phase)
• Simultaneous monitoring of current overshoot and
undershoot with a singe device
Phase failure, open circuit
✓
(Two-phase)
✓
(Three-phase)
• Minimizes heating of three-phase motors during phase
failure through immediate disconnection
•
Prevents operation of hoisting equipment with reduced
load carrying capacity
Phase sequence monitoring
--
✓
(Selectable)
• Prevents starting of motors, pumps or compressors
in the wrong direction of rotation
Internal ground-fault detection
(residual current monitoring)
--
✓
(Selectable)
• Provides optimum protection of loads against
high-resistance short circuits or ground faults due to
moisture, condensed water, damage to the insulation
material, etc.
• Eliminates the need for additional special equipment
and thus space in the control cabinet
• Reduces wiring overhead and costs
Blocking current monitoring
--
✓
(Selectable)
•
Minimizes heating of three-phase motors when blocked
during operation through immediate disconnection
• Minimizes mechanical loading of the system by acting
as an electronic shear pin
Features
RESET function
✓
✓
• Allows manual or automatic resetting of the relay
• Resetting directly on the device or by switching the
control supply voltage off and on (remote RESET)
ON-delay time
0 ... 60 s
0 ... 99 s
•
Enables motor starting without evaluation of the starting
current
•
Can be used for monitoring motors with lengthy start up
Tripping delay time
0 ... 30 s
0 ... 30 s
• Permits brief threshold value violations
during operation
• Prevents frequent warnings and disconnections with
currents near the threshold values
Operating and indicating elements
LEDs and
rotary potentiometers
Displays and buttons
• For setting the threshold values and delay times and
for fast and targeted diagnostics
• For selectable functions
• Displays for permanent display of measured values
Integrated contacts
1 CO contact
1 CO contact,
1 semiconductor output
• Enable disconnection of the system or process when
there is an irregularity
• Can be used to output signals
Features
3RR21
3RR22
Benefits
© Siemens AG 2016