ABB RED615 Technical Manual page 532

Section 4
Protection functions
526
Stall protection
This module is activated only when the selected Operation mode setting value is
"IIt & stall" or "IIt & stall, CB".
The startup current is specific to each motor and depends on the startup method
used, such as direct online, autotransformer and rotor resistance insertion. The
startup time is dependent of the load connected to the motor.
Based on the motor characteristics supplied by the manufacturer, this module is
required if the stalling time is shorter than or too close to the starting time. In such
cases, a speed switch must be used to indicate whether a motor is accelerating
during startup or not.
At motor standstill, the STALL_IND input is active. It indicates that the rotor is
not rotating. When the motor is started, at certain revolution the deactivation of the
STALL_IND by the speed switch indicates that the rotor is rotating. If the input is
not deactivated within Lock rotor time, the OPR_STALL output is activated.
The module calculates the duration of the motor in stalling condition, the
STALL_RL output indicating the percent ratio of the start situation and the set
value of Lock rotor time. The value is available in the monitored data view.
The activation of the BLOCK input signal resets the operation time and deactivates
the OPR_STALL output.
Cumulative startup protection
This module protects the motor from an excessive number of startups.
Whenever the motor is started, the latest value of START_TIME is added to the
existing value of T_ST_CNT and the updated cumulative startup time is available
at T_ST_CNT. If the value of T_ST_CNT is greater than the value of Cumulative
time Lim, the LOCK_START output is activated and motor restarting is inhibited
during the time the output is active. The LOCK_START output remains high until
the T_ST_CNT value reduces to a value less than the value of Cumulative time
Lim. The start time counter reduces at the rate of the value of Counter Red rate.
The LOCK_START output becomes activated at the start of MOT_START. The
output remains active for a period of Restart inhibit time.
1YHT530004D05 D
615 series
Technical Manual