Siemens SIMATIC ET 200pro Quick Manual page 153

Principle of blocking protection when powering up
The following diagram illustrates the block protection principle when powering
up, that is, the relationship between the blocking current and blocking time:
Case 1: Motor continues to run
Blocking
current
Motor
current
Case 2: Motor is switched off
Blocking
current
Motor
current
Figure 10-4: Principle of blocking protection
Principle of blocking protection after powering up
After powering up, the blocking protection runs in continuous operation as
follows:
• The blocking time is reduced independently of the parameterized value to 1 s.
• The blocking current is limited to a max. 400%.
With a parameterized blocking current < 400%, the parameter value is valid.
• When the blocking protection is activated, the motor starter itself generates a
trip command.
• The signals "Motor block tripping" and "General fault" are generated.
• The maximum pointer "Number of switching element overload trippings" is
increased by 1.
SIMATIC – ET 200pro motor starter
GWA 4NEB 950 5661-02 DS 04
Blocking
I
Blocking time
Blocking
I
Blocking time
Blocking
Removed within blocking time
Motor continues to run
t
Blocking
after blocking time has elapsed
still present
Motor is switched off
t
10-13