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MICROMASTERMICROMASTER VectorMIDIMASTER VectorMotor Data7. MOTOR DATA7.1 Engineering InformationA detailed description of the motors is provided in thefollowing catalogues:M 11:DA 47:DA 48:LV motors: Squirrel Cage Induction motorsReluctance motors: Synchronousmotors for variable-speed drivesSIEMOSYN motors: permanentmagnetsynchronous motorsForce-ventilated Motors:In addition to self-ventilated 1LA5 1LA6 and 1LA7 motors,force-ventilated 1LA5/1LA7 motors can also be used.According to Figure 1, the permissible S1-torque can beused, at rated frequency, down to standstill.It is practical to use force-ventilated motors, if high torqueutilisation is required, even at the lowest speeds.Standard motors with pole numbers greater than 4 are to beoperated at speeds > approx. 2200 RPM (e.g. in the fieldweakeningrange). Thus, for self-ventilated motors the fannoise is decreased.The engineering guidelines specified here refer to Siemens1LA5, 1LA6 and 1LA7 induction motors as well as Siemensforce-ventilated 1LA5 motors. If third-party induction motorsare used, their specific engineering data must be observed.All types of load characteristics are possible; only the mostimportant will be discussed here:- Constant-torque DrivesWhen M = const. ("Constant Torque", CT)- Fan and pump driveswith M ~ n² ("Variable Torque", VT).M/Mn%100908070Constant flux rangeFor forced ventilationField-weakening rangeUtilized to temperature rise class FUtilized to temperature rise class BTorque Utilisation of Motors:60The motor best suited for a specific application depends onits permissible torque characteristic over the speed range.10 20 30 40 50 60 70 80f [Hz]The typical characteristics of the permissible continuoustorque for a self-ventilated motor with a 50 Hz rated frequencyare illustrated in Figure 1. As a result of the low cooling effectat low speeds, the torque which can be utilised is significantlylower than at 50 Hz. The torque de-rating factor is not thesame for all motors. The assignment tables from Page 7/6onwards specify the torque de-rating as a function of thespeed in the frequency range of f = 0 Hz to 50 Hz whenutilised to temperature rise class F.For frequencies above rated frequency f n, the voltage remainsconstant when the maximum drive converter output voltagehas been reached. In this range, the motor is operated in fieldweakening. The torque which can be thermally utiliseddecreases with approx. f n/f. As the stall torque decreases with(f n/f) 2 , the safety margin to the stall torque decreases and thedrive load capability is lower.Figure 1: Typical Characteristic Of The PermissibleTorque For Force-Ventilated Motors(e.g. 1LA5/1LA6/1LA7) with 50 Hz RatedFrequency.(Precise values for 1LA5, 1LA6 and 1LA7motors can be taken from the AssignmentTables on Page 7/6 onwards).Maximum Speeds:The maximum mechanical speeds for 1LA5, 1LA6 and 1LA7motors are specified in Catalogue M11.For MICROMASTER and MIDIMASTER drives with a fieldweakeningrange f = 50 Hz to 100 Hz, the output up to 100 Hzdecreases for 1LA5, 1LA6 and 1LA7 motors by approximately10%.The assignment tables indicate that Siemens1LA5/1LA6/1LA7 induction motors, when utilised according totemperature rise class F, in the control range 1:2, cangenerally be operated at 100% rated torque. When utilisedaccording to temperature rise class B, the permissible torquefor 1LA5/1LA6/1LA7 motors must be reduced byapproximately 10%.Siemens DA 64 – 1998/99 (04/99) 7/1