Analog Input Configuration - ABB RELION REX640 Technical Manual

1MRS759142 C
4.10.4
4.10.5
REX640
Technical Manual
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 start-up 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 start-ups. Upon
exceeding the specified number of start-ups 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.

Analog input configuration

STTPMSU has one analog group input which must be properly configured.
Table 933: Analog inputs
Input
I3P
See the preprocessing function blocks in this document for the
possible signal sources.
Improper analog channel configuration causes a validation error if the analog
channels are not completely configured or they do not match with certain settings. For
troubleshooting, check the contents of this chapter and also the preprocessing blocks
in this document. The configuration can be written to the protection relay once the
mismatch is corrected.
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of STTPMSU can be described with a module diagram. All the modules
in the diagram are explained in the next sections.
Protection functions
Description
Three-phase currents
Section 4
993