ABB RELION 620 Series Technical Manual page 400

Section 4
Protection functions
394
The thermal level at the beginning of the startup condition of a motor and at the end of the
startup condition is available in the monitored data view at the THERMLEV_ST and
THERMLEV_END outputs respectively. The activation of the BLOCK input does not have
any effect on these outputs.
Alarm and tripping logic
The module generates alarm, restart inhibit and tripping signals.
When the thermal level exceeds the set value of the Alarm thermal value setting, the
ALARM output is activated. Sometimes a condition arises when it becomes necessary to
inhibit the restarting of a motor, for example in case of some extreme starting condition
like long starting time. If the thermal content exceeds the set value of the Restart thermal
val setting, the BLK_RESTART output is activated. The time for the next possible motor
startup is available through the monitored data view from the T_ENARESTART output.
The T_ENARESTART output estimates the time for the BLK_RESTART deactivation
considering as if the motor is stopped.
On the rising edge of the emergency start signal START_EMERG is set high, the thermal
level is set to a value below the thermal restart inhibit level. This allows at least one motor
startup, even though the thermal level has exceeded the restart inhibit level.
When the thermal content reaches 100 percent, the TRIP output is activated. The TRIP
output is deactivated when the value of the measured current falls below 12 percent of
Rated current or the thermal content drops below 100 percent.
The activation of the BLOCK input blocks the ALARM, BLK_RESTART and TRIP
outputs.
1MAC504801-IB E
620 series ANSI
Technical Manual