Service and diagnostics interfacesThe proper function is indicated through 3 LEDs.1. operation: excitation „ON“, device is working2. ready-to-operate: devices receives voltage, no error3. error: flashing:systemfaulty,resetispossible;

persistently: device is out of orderThereisaRS232interfaceortheCANbusforservice(soft-ware updates) and diagnostics.

TheexcitationdeviceVEMRLAQX16007-BAhasbeenspe-ciallydevelopedfortheexcitementofbrushlesstractiongene-ratorswhichareused inmoderndiesel-electric locomotives.

Theexcitationdeviceisbuiltinaseparatehousingforunder-floor installationand ismounted toacoolingelementon theoutersideofthelocomotiveasareplaceableunit.Theexcitationdevice comeswith corresponding electrical interfaces to thegenerator, to the supply voltages as well as to the superordi-natecontrolofthelocomotive.

The excitation device consists of a 3-phase inverter, which is directlypoweredbyastarterbattery.Togetherwithaspeciallyengineered exciter of the traction generator, the contactless transmission of the exciting energy into the developing fieldofthegeneratorisalreadypossibleduringthenon-operatingstate of the generator. The following operating modes are distinguished through the excitation device:• Normalmode, the excitation device gets the control signals andsetvaluesfromthemaincomputerthroughCAN-bu-ses,messagesandnominalvaluesaresentviaCAN.

• Startingmode, i.e. starting of the diesel engine through the motor-drivenoperatingofthetractiongenerator.

• Generatormode, the voltage control within the traction intermediatecircuitdependsonrotationspeedandload.Thenominalvoltage,theactualvoltageaswellasthegenerator’s rotation speed are indicated via CAN. The controlcircuitisconnectedthroughtheintermediatecircuitvoltage.

• Brakingmode, the traction inverters feed the traction inter-mediatecircuitwithenergy.Theexcitationdeviceworksatthelowerexcitingcurrentlimitwhichisdependentonthe rotation speed during controlled operation. The control circuit is opened.

• Emergencymode, the excitation device works with saved valuesforexcitingcurrentandoutputfrequency.Thecom-munication(messages,controlsignals)isrealisedthroughbinaryinterfaces.

Control conceptThecontrolisbasedoneffectivevalues.Inordertoreachhighcontroldynamics,thevoltagecontrolusesaPIalgorithmwitha subordinate excitement current control. There is a settinglimit for thevoltagecontrolwhichgoesalongwithadefinedgenerator characteristic. For this purpose the generator´s rota-tionspeedisprovidedviaCANinadditiontotheintermediatecircuit voltage within the traction circuit.

Monitoring featuresSelfprotectionTheselfprotectionof theexcitationdevice’spoweramplifiercomprises the over-current protection, the over-temperatureprotectionand thevoltageprotection.Thesoftwaremonitorsthe intermediatecircuit’svoltagewithin theexcitationdevice.Ifavalueexceedsorfallsbelowthenominalvalue,themaincomputerreceivesamessageviaCAN.

GeneratorprotectionTheexcitationdevice’ssoftwaremonitorsthefollowingvaluesinordertopreventdamagestothegenerator:• the generator temperatureonuptosixdifferentPT100measuringpoints.ThesearethentransmittedtothemaincomputerasactualvaluesviaCAN.Thereactioncomprisestwostages,message„warning“andmessage„error“com-binedwiththelockingoftheexcitationdevice.

• the condition of the rotating diodes within the generator.• the symmetry of the fed 3-phase exciting currents.• the insulation resistance of the excitation winding.• adherence to the lower and upper limit values for the exci-

ting current as a function of the generator’s rotation speed.• themaximumadmissiblestarting time aswellasthema-ximumadmissiblenumberofsubsequentstarts attempts. Theexcitationdeviceenablestheconnectionofthestartingconverter for the generator’s stator winding.

Warningsorerrormessagesaretransmittedtothemaincom-puter via CAN.

Upgrade optionsThemodularstructureof theexcitationdevice (consistingofdigital control system, signal processing and power section)enablestheoptimaladjustmenttotherespectiveapplication.