4.8 Motor startup supervision STTPMSU
4.8.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Motor startup supervision STTPMSU Is2tn< 49,66,48,51LR
4.8.2 Function block
GUID-A37CF63B-5273-423B-9DC3-AACADB668AEE V1 EN
Figure 272: Function block
4.8.3 Functionality
The motor startup supervision function STTPMSU is designed for protection
against excessive starting time and locked rotor conditions of the motor during
starting. For a good and reliable operation of the motor, the thermal stress during
the motor starting is maintained within the allowed limits.
The starting of the motor is supervised by monitoring the TRMS magnitude of all
the phase currents or by monitoring the status of the circuit breaker connected to
the motor.
During the startup period of the motor, STTPMSU calculates the integral of the I²t
value. If the calculated value exceeds the set value, the operate signal is activated.
STTPMSU has the provision to check the locked rotor condition of the motor using
the speed switch, which means checking if the rotor is able to rotate or not. This
feature operates after a predefined operating time.
STTPMSU also protects the motor from an excessive number of startups. Upon
exceeding the specified number of startups within certain duration, STTPMSU
blocks further starts. The restart of the motor is also inhibited after each start and
continues to be inhibited for a set duration. When the lock of start of motor is
enabled, STTPMSU gives the time remaining until the restart of the motor.
STTPMSU contains a blocking functionality. It is possible to block function
outputs, timer or the function itself, if desired.
1YHT530004D05 D Section 4
Protection functions
615 series 521
Technical Manual
To Next Page
Loading...
Need help?
General
