Sepam - HV/MV Protection and control units (ENG) - Trinet

Excessive starting time and locked rotorANSI codefunction n°IIs0.05Ib51LRF441OperationThis function is three-phase.It comprises two parts:c excessive starting time: during starting, this protection picks up when oneof the 3 phase currents is greater than the set point Is for a longer time periodthan the time delay ST (normal starting time),c locked rotor: at the normal operating rate (post starting), this protection picks upwhen one of the 3 phase currents is greater than the set point Is for a longer timeperiod than the time delay LT of the definite time type.Starting is detected when the absorbed current is 5% greater than the Ib current.The time delay ST which corresponds to the normal starting time may bereinitialized by a logic data input for a particular use.F441/1STBlock diagramF441/2F441/5F441/3F441/4F441/5Case of normal startingI1I2I3I>0.05Ib ST 0u1K854&&LT0u1F441/2F441/3F441/4II>Is&F441/1Is0.05IbSTF441/1F441/2F441/3F441/4F441/5Case of excessive starting timeCommissioning, settingsCheck:c the connections,c the positions of the microswitches SW associated with the current inputs,c the general parameters in the status menu.Set the following:c Is set point: Is is set as a percentage of the operating currrent (Ib). The value ofIs must be between the operating current (Ib) value and the starting current value.999 % Ib may be set to disable the protection: all the outputs are set to zero:c ST time delay: ST corresponds to the normal starting time;c LT time delay: LT is designed for reacceleration which is not detectedas being a restart.IIs0.05IbF441/1STLTF441/2F441/3F441/4F441/5Case of a locked rotor2/38 Protection functions