Substation Monitoring - Siemens SIMATIC ET 200SP Manual

Example for the minimum idle time (T
The graphic below shows the minimum idle time of a 12 A motor starter with the following
parameters:
I
rated_motor
I
startup/Irated_motor
T
Startup
3.7.7

Substation monitoring

You can determine various system states with the help of the motor current and the current
limits.
System state
Motor operates more sluggishly,
e. g. due to bearing damage
Motor operates more smoothly,
e. g. because the system has run out of
processing material.
Motor is blocked
Open circuit
•
Defective fuse
•
Motor idling
•
Power failure
•
No load connected
•
Motor starter (3RK1308-0**00-0CP0)
Manual, 12/2016, A5E34821005002A/RS-AB/002
) 12 A motor starter at I
Off
= 10.4 A
= 8.6; thus: I
Startup
= 0.125 s T ≥ 19 s
Off
Current value
Current is higher than normal
Current is lower than normal
Very high current flowing
Very low current flowing
Minimum load undershot
Startup/
≈ 89 A
Product overview
I = 8
rated
Protection by:
Current limits
Current warning limit
Blocking protection
Residual current detection
3.7 Functions
51