Siemens SIRIUS M200D - Asymmetry Monitoring

Functions
3.7 System monitoring
M200D PROFIBUS/PROFINET
52 Manual, 08/2014, A5E01577426A/RS-AA/004
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
Device parameter
Default setting
Setting range
Response to asymmetry Trip
• Warning
• Trip
Asymmetry limit 30%
• 30 ... 60%
• 0 = deactivated
Increment: 10%
Messages and actions
Message
Action
Asymmetry detected Dependent on parameterization
Asymmetry tripping Trip (asymmetry exists)