Operating Instruction - Frequency Inverter 230V / 400V ... - opis.cz

17.5 Motor Circuit BreakerMotor circuit breakers are used for protecting a motor and its supply cable againstoverheating by overload. Depending on the overload level, they disconnect the motorfrom mains supply immediately in the case of a short-circuit or they disconnect themotor if an overload has occurred for some time.Conventional motor circuit breakers arecommercially available for various applicationswith different trigger characteristics (L,G/U, R and K), as shown in the diagram onthe right. As frequency inverters in mostcases are used for supplying motors whichare classified as operating equipment withvery high starting currents, only the K characteristicwas realized in this function.Unlike the operation of a conventional motorProtection switch which disconnects theequipment to be protected immediately ifthe trigger threshold is reached, this functionprovides the possibility of issuing awarning instead of disconnecting the equipmentimmediately.The rated current of the motor protectionswitch refers to the rated motor currentstated via parameter Rated Current 371 ofthe corresponding data set.The rated values of the frequency inverterare to be considered accordingly when itcomes to dimensioning the application.1/1000 seconds seconds minutesx nominal currentThe function of the motor circuit breaker can be linked to different data sets. In thisway, it is possible to operate different motors via one frequency inverter. Thus, eachmotor can be equipped with its own motor protection switch.In case a motor is operated via the frequency inverter for which some setting values,e.g. minimum and maximum frequency, are changed via the data set switch-over,only one motor circuit breaker may be installed. This functionality can be differentiatedby selecting the parameter Operation Mode 571 for single motor operation ormultiple motor operation.Operation modeFunction0 - Off The function is deactivated1 -2 -11 -22 -K-Char.,Mul.MotorOp.,Err.Sw.OffK-Char.,Sing.Motor,Err.Sw.-OffK-Char.,Multi-MotorOp.,WarningK-Char.,Single-Motor,WarningIn each of the four data sets, the rated values aremonitored. Overloading the drive is prevented by thefault switch-off "F0401".The rated values in the first data set are used independentlyof the active data set. Overloading the driveis prevented by the fault switch-off "F0401".In each of the four data sets, the rated values aremonitored. Overloading the drive mechanism is signaledby a warning message "A0200".The rated values in the first data set are used independentlyof the active data set. Overloading the drivemechanism is signaled by a warning message "A0200".166 02/06