Siemens SIMATIC ET 200pro - Page 153

SIMATIC – ET 200pro motor starter
GWA 4NEB 950 5661-02 DS 04
10-13
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:
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.
Blocking time
Motor
current
Blocking
current
I
t
Case 1: Motor continues to run
Blocking
Blocking
Motor continues to run
Removed within blocking time
Blocking time
Motor
current
Blocking
current
I
t
Blocking
Blocking
Motor is switched off
after blocking time has elapsed
Case 2: Motor is switched off
still present