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18-06-08 PVD3668_GB_GVM_June_2018 
3.1.4.  Inverter selection 
The Inverter selection depends on at first on the available voltage and then on its rated power, 
nominal current and maximum electrical frequency have to be achieved by the drive and by 
the flux weakening ratio. 
 
Please refer to the drive technical documentation for any further information 
and to select the best motor and drive association. 
In case of using a Low Voltage inverter that will bring high current levels, 
take care to the 3 phase cables cross-section and length that can affect 
the motor speed or its rated point. 
In  flux  weakening  mode,  please  refer  to  the  inverter  technical 
documentation  to  select  the appropriate  inverter regarding  maximum 
voltage and current …. 
Max back emf of the motor must be lower than the max voltage (from the 
motor) supported by the inverter 
Please refer to the drive technical documentation 
The inverter must be able to manage the flux weakening and must avoid 
voltage higher than the nominal motor voltage at the motor terminals. 
Please, check field weakening ratio supported by the inverter. 
Field weakening ratio = Max speed divided by the basis speed 
Due to the maximum electrical frequency able to be managed by the 
inverter, the motor has a speed limitation given as follows: 
Please take care that the drive the GVM is connected to have a short 
enough dv/dt not to generate any transient current effect in the motor 
bearings.  
 
polesNumber_of_
60*cy(Hz)er_frequenMax_invert*2
rpmlimitation Speed