Altistart 48 Enclosed Altistart 48 Soft Starters Page 11 Functions

11 Altistart 48 soft starters for asynchronous motors Protection Functions Functions (continued) Protection functions (continued) Motor underload protection The soft starter detects a motor underload if the motor torque falls below a preset torque threshold ( LUL ) for a specific (adjustable) period of time ( tUL ). The motor underload threshold can be set between 20% and 100% of the nominal motor torque. The permissible underload duration can be set between 1 and 60 s. The detection function ( ULL ) can trigger an alarm or a detected fault. The detection function can be disabled. The "motor underload detected" alarm can be indicated by a configurable logic output or displayed via the serial link. The "motor underload detected" fault (ULF) locks the soft starter and can be displayed via the serial link. Excessive acceleration time protection This protection function can be used to detect a start which takes place in adverse conditions. Examples of such conditions include a locked rotor or a motor unable to reach its nominal rotation speed. If the start duration is longer than the set value (between 10 and 999 s), the soft starter enters detected fault mode. The function can be disabled. Current overload protection The soft starter detects a current overload if the motor current exceeds a preset overcurrent threshold ( LOC ) for a specific adjustable period of time ( tOL ). The overcurrent threshold can be set between 50% and 300% of the nominal motor current. The permissible overcurrent duration can be set between 0.1 and 60 s. This function is only active in steady state. The detection function ( OIL ) can trigger an alarm or a detected fault. It can also be disabled. The "current overload detected" alarm can be indicated by a configurable logic output or displayed via the serial link. The "current overload detected" fault (OLC) locks the soft starter and can be displayed via the serial link. Protection against line phase inversion This function can be used to detect the direction of rotation of the motor phases and, if it is enabled, to indicate a detected fault when the direction of rotation is reversed. Time before restarting This function can be used to avoid several consecutive starts which may cause: Thermal overheating of the application A detected thermal fault, which may require maintenance work Overcurrents (if direction of rotation is reversed) or repeats (run/stop command) After a stop command, the motor can only restart after the preset time delay has elapsed. The motor is restarted when the time delay has elapsed if a run command is still valid or if a new run command is sent. Adjustment range: 0 to 999 s. Motor phase loss detection The function is used to adjust the sensitivity of the protection function to detect a loss of current or a low current in one of the three motor phases for at least 0.5 s or in all three motor phases for at least 0.2 s. The value of the minimum current level can be set between 5% and 10% of the soft starter nominal current. Automatic restart This function permits up to six restart attempts after locking on a detected fault at intervals of 60 s if the cause of the detected fault has been removed and if the run commands are still present. After the sixth attempt, the soft starter remains locked and the detected fault must be reset before a restart is permitted. If the function is active, the fault relay remains activated if line phase loss, motor phase loss, or line frequency out of tolerance faults are detected. This function can only be used in 2-wire control. 20% 100% Time (sec) LUL +10% Motor Nominal Torque (Tn) ULL < t LUL tUL Motor underload detection ( ULL ) 50% 300% Motor Current (I) Time (sec) OIL tOL t < tOL LOC -10% LOC Motor overcurrent detection ( OIL )

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