User manual 09/2009 - Schneider Electric

The Protection FunctionLong Time ProtectionPresentationLong time protection on the Micrologic 6 E-M trip unit is adapted to protecting all types of motorapplication against overload currents.Operating PrincipleLong time protection is I 2 t IDMT:• It incorporates the motor thermal image function.• It can be configured as the Ir pick-up and as the trip class Cl.Tripping curve:No. Parameter Description0 In Trip unit setting range: The maximum setting corresponds to the trip unit rating In1 Ir Long time protection pick-up2 Cl Long time protection trip class (according to standard IEC 60947-4-1)NOTE: The SDTAM module early tripping protection function can be used to command contactor opening(see SDTAM Module Option, page 57).Setting the Long Time ProtectionThe Ir pick-up can be set as follows:• On the Micrologic trip unit, preset by the Ir dial and fine-tuned on the keypad• Via the communication option using the RSU software, preset by the Ir dial on the Micrologic trip unitand fine-tuned via the RSU softwareThe trip class Cl can be set as follows:• On the Micrologic trip unit, set on the keypad• Via the communication option using the RSU softwareLV434104 09/2009 59