Permanent Magnet Synchronous Motors For Inverter Operation

Technical explanationsRated voltage and frequencyMotor protectionIn the basic version, motors are supplied for mains power systems with 400 V and 50 Hz (complies with inverter input voltage). The motors can only be operated in connection with afrequency inverter.Rated voltage and frequency will be adjusted to the technicalrequirements of the drive. The rated voltage (fundamental waveoutput voltage) of the PM synchronous motors is always smaller than the mains voltage. The rated frequency complies withthe required rated speed.The following variations of motor protection are possible, ifordered:-- motor protection with thermistor temperature sensors in thestator winding-- bimetal temperature sensor as opener or closer in the statorwinding-- silicon diodes KTY-- resistance thermometer to monitor winding or bearing temperature-- bearing vibration diagnosisMotor torqueBearings/bearing lubricatioThe design torque in Nm given at the motor shaft will bePM 9550 ·nwhereP design output in kWn speed in rpmType designationPE1R160MX4KTY1234567891Design versionP Permanent magnet synchronous motor2Design condition2 Series 2E Energy saving motor3Standard characteristic numberm0 IEC, progressive design series1 DIN design2 Transnorm design, IEC4Degree of coolingR . Fin cooled, IC 411F Forced-air cooled, IC 416B Water cooled, IC 31W5Shaft height in mm56, 63, 71, 80, 90, 100, 112, 132, 160, 180, 200, 250,280, 315, 3556Foot lengthK smallG largeS . shortM . mediumL . long7Symbols for different outputX, Y, Z .8Pole number4, 6, 8, 129Special designsKTY Temperature detector KTY for further symbols refer to Modifications summaryBase catalogue 01-20108VEM motors are equipped with anti-friction bearings from respected manufacturers. The rated bearing lifetime is at least20,000 h with the exploitation of the maximum permissible load.The rated bearing lifetime for motors installed in a horizontalposition without additional axial loading is 40,000 h in the caseof coupling service.The versions fixed bearing at N-end, without fixed bearing(floating bearing arrangement), permanent lubrication, relubrication device, heavy bearing on D-end (for increased lateralforces), easy bearing arrangement and the bearing schedulesdisk spring or wave washer types, V-ring types and figures ofbearing arrangement can be taken from the overviews of thebearing arrangements.The respective flat grease nipples are contained in the tablesof the design drawings. Motors in the normal versions with twodeep groove ball bearings have preloaded bearings, where thepreloading is implemented by a disk spring or a wave washer.Versions with cylindrical roller bearings on the D-end (heavybearing arrangement VL) are excepted from the preloading.The “fixed bearing N-end” version is possible in the case of motors without a “fixed bearing”. Fixed bearing at D-end possibleon request.The most important prerequisite for achieving the normal bearing lifetime is correct lubrication, i.e. the use of the right kind ofgrease according to the application, the filling with the correctamount of grease and the maintenance of the subsequent relubrication periods.The frame sizes 56 to 160 are equipped with life-lubricatedbearings. These bearings are to be changed promptly in accordance with the usable grease life.In the case of motors from size 180, the bearings must be relubricated promptly in accordance with the usable grease life.Under normal operating conditions, the lubrication filling will allow 10,000 operating hours for the 2-pole version and 20,000operating hours for the 4-pole version without relubrication.Under normal service conditions, for version with relubricationdevice, 2,000 or 4,000 operational hours will apply. A greaseof type KE2R-40 as specified in DIN 51825 will be used asstandard grease. The used grease is to be removed from thelubrication chamber in the external bearing cover after five relubrications.A change of bearings is only possible when using suitableequipment. The best solution is to ask an authorized servicecentre (see also installation, operation and maintenance manual). Information about bearing sizes, grease types and quantities and times for relubrication are to be taken from an additional plate attached to the motor.

Technical explanationsBearing monitoringThe motors can be prepared for equipment of or equipped withtemperature detectors, shock pulse and vibration detectors forbearing monitoring. PT100 can be fitted on the bearings astemperature sensors.They can be designed in 2-, 3- or 4-wire circuit. The connectionis either done in the main terminal box or in a separate auxiliaryterminal box that is fixed at the main terminal box or on themotor housing depending on the design. For wear monitoringof the anti-friction bearings it is possible for size 132 and biggerto install shock pulse sensors (SPM) at the end shields. Thus amonitoring with mobile recorders is possible. For remote monitoring it is also possible to use permanently wired shock pulseor vibration sensors.Use of insulated bearingsMagnetic unbalances induce a voltage in the shaft of the motors. This shaft voltage results in equalising currents betweenrotor and stator leading through the bearings. If the voltage rises above a limit value of 500 mV, bearings can be damaged.Because of the design this value will not be exceeded in anycase for VEM standard motors at mains operation. Howeverthese effects can be amplified by frequency inverter operation,whereas the design of the inverter is one of the most importantinfluences. Pulse inverters generate especially high frequencyvoltages and currents depending on the pulse frequency andthe pulse modulation. Output filters in the inverter minimise these effects.To avoid bearing damages motors in size 315 and above arefitted with insulated bearings on N-end as standard.Winding and insulationVEM motors of design series P2./PE. are produced in thermalclass 155 [F] as standard. High quality enamelled copper wiresand insulation materials combined with an impregnation treatment based on low-solvent varnish are used. These materialsoffer a high mechanical and electrical strength and guarantee along life time of the motors. A design in thermal class 180 [H/F]is available (additional charge).Inverter supply means higher voltage loads for the motor winding than sinusoidal mains supply. Therefore the winding insulation of the motor must be selected according to the . permitted valuesUdu/dt[V][kV/µs] 1,000 0.556-132T acc. to 1,350Sp.2945 1.0132[P20. 112]to 355 1,350 1.556-132T acc. to 1,560Sp.9382 3.0132 [PU0. 112]to 355 1,850 5.0 2,500 5.056-132TPV1./PV0. 132[PV0. 112]to 355Motors for inverter operation in VIK design(VIK 04.2005)Output voltages at the inverter 690 VAccording to VIK recommendation 04.2005, no. 6.7 / NAMURrecommendation NE38, motors are permitted to be operatedwith a maximum peak voltage of1,350 V complying with DIN IEC 60034-17 and a voltage risetime du/dt of 1.5 kV/µs at the motor terminals. Higher peak voltages must be agreed separately. This means VIK motors forinverter operation are produced in design PE./P2. if no othervoltage peak values are agreed. It is not allowed to use permanent magnet motors in zone 2.Wiring, grounding and EMCAll motors must be connected with shielded, symmetric cablesand EMC cable glands (glands with 360 -shield contacting) toassure a proper grounding and design complying with the EMCregulation. The 360 grounding has to be done for all cable entries according to the product related information for the cableglands. It must be assured to have the best available potentialequalisation between motor housing and inverter. Thus it is prevented to induce a grounding current through the motor shaft inthe working machine.Types of constructionThe most frequently used types of construction are shown inthe following table. Other types of construction on request. Thetype of construction is designated on the nameplate accordingto Code I, DIN EN 60034-7. Standard motors in sizes 56 – 200that are ordered in the basic types of construction can also beused in the following other types of construction:IM B3 in IM B5, IM B7, IM B8 und IM V6IM B35 in IM 2051, IM 2061, IM 2071 und IM V36IM B34 in IM 2151, IM 2161, IM 2171 und IM2131IM B5 in IM V3IM B14 in IM V19Motors of types IM V5, IM V1 or IM V18 may optionally be fittedwith a protective roof to prevent smaller parts from falling intotheir interior. For types with the shaft end pointing upward theuser must provide a suitable covering to prevent smaller partsfrom falling into the fan cover.The cooling air flow must not be obstructed by the covering. Asfrom frame size 225, consultation with the manufacturer will benecessary for the types IM V5, IM V6, IM B6, IM B7 and IM B8.In the frame size range as of 315L, the types IM B5 and IM V3are not available.9

Technical explanationsOverview of types of constructionBasic types ofconstruction10Derived types of constructioIM B3IM 1001IM V5IM 1011IM V6IM 1031IM B6IM 1051IM B7IM 1061IM B8IM 1071IM B35IM 2001IM V15IM 2011IM V36IM 2031IM 2051IM 2061IM 2071IM B34IM 2101IM 2111IM 2131IM 2151IM 2161IM 2171IM B5IM 3001IM V1IM 3011IM V3IM 3031IM B14IM 3601IM V18IM 3611IM V19IM 3631

Technical explanationsDesign versionShaft heightSeriesMaterial forHousingEnd shieldsFeet63 to 132TP.1Rbolted on100 LXP.1Rcast on132 to 280P.1Rbolted on315, 355P2.R56 to 100P20R112 to 250P20Rbolted on280 to 315P20Rcast onGrey castironFoot mountingcast oncast onFigure 1: principle design of PM motorFigure 2: principle design of PM motorFigure 3: PM rotor complete, with bandageFrom the outside PM motors don’t differ from asynchronousmotors (ASM). The design is based on the robust and reliable VEM standard motors in grey cast iron housing. The statorcomplies with the basic series K2.R. In addition the squirrelcage of the ASM is used as basis for the magnet wheel (rotor).The rotor body of the squirrel cage motor is turned after diecasting, then the neodymium magnets are fixed by gluing andafterwards they will be bandaged (see figure 2 and 3).11

Technical explanationsCooling and ventilationThe motors are equipped with radial plastic or aluminium alloyfans, which cool independently of the direction of rotation of themotor (IC 411 as specified in DIN EN 60034-6).Attention is to be paid that a minimum distance of the fan coverfrom the wall is maintained (dimension Bl) when the motor isbeing installed.Hints for calculation of drive design and for operation ofmotors in connection with frequency invertersMotors are only one part of a complex electric drive system.However a poor design of the drive system will mainly showin motor operation, whereas a faulty parameterisation will benoticed at the mechanical transmission elements like couplingsand belt drives. Modern inverters mostly protect themselvesand the motor against thermal overload. But unacceptable highvoltage peaks at the motor terminals will not be recognized.The drive can have problems if the output circuit is missing atthe inverter and/or the cables are too long. In addition this oftenresults in serious damage of the motor insulation.There are several options to optimise the drive system:-- Output filter circuits at the inverter (choke, du/dt filters or sinefilters)-- Motor with reinforced insulation system-- Combination of both optionsThe planning of whole drive systems is bound to the knowledgeof the interaction of all used components.The planning engineer has to select the different componentsvery carefully. It is mainly his responsible decision that, at themotor terminals, the permissible voltages are not exceeded.This includes also the decision about the motor insulation system, always taking the effects of the other components into account.Examples for drive components having decisive influences onthe motor insulation system:Motor cable(Length, type, wiring, shielding, etc. )Long motor cables can induce unacceptable pulse voltages atthe motor terminals. The impact of long motor cables can bereduced by the following components that ar

nent magnet synchronous motors (PM motors). They are operated exclusively with frequency inverters and are characterised by a significantly higher efficiency ( IE3) and an improved part load behaviour than asynchronous motors. In addition PM-motors can reach a higher output than asyn-chronous motors of the same size. Because of the rotor fol-