Asymmetry Monitoring - Siemens SIRIUS M200D Manual

Functions
3.7 System monitoring
3.7.2

Asymmetry monitoring

Description
Three-phase induction motors respond to slight asymmetries in the supply voltage with a
higher asymmetric current consumption, which causes the temperature in the stator and
rotor windings to increase. In this case, the M200D motor starter protects the motor against
overload by shutting it down.
Note
When the motor is switched on, asymmetry evaluation is suppressed for approx. 0.5 s.
Asymmetry limit
The asymmetry limit is a percentage value by which the motor current is allowed to deviate
in each phase.
Asymmetry exists when the difference between the smallest and the greatest phase current
is greater than the parameterized asymmetry limit.
The reference value for the analysis is the maximum phase current in one of the 3 phases!
Response to asymmetry
You use this device parameter to specify how the motor starter is to behave in the event of
asymmetry:
● Warning
● Trip
Settings
Response to asymmetry
Asymmetry limit
Messages and actions
Asymmetry detected
Asymmetry tripping
52
Device parameter
Message
Default setting
Trip
•
•
30%
•
•
Increment: 10%
Action
Dependent on parameterization
Trip (asymmetry exists)
M200D PROFIBUS/PROFINET
Manual, 08/2014, A5E01577426A/RS-AA/004
Setting range
Warning
Trip
30 ... 60%
0 = deactivated