I would say the base voltage is the voltage at which the base speed is maintained. Max voltage would be the voltage at which speed would not increase without changing the vector.
Maybe have a look at this doc:
**broken link removed**
base is for optimum op from anything you are using and the maximum voltage is the voltage where the op is relatively efficicent and there is a satisfied performance from the device
generally use device in base voltage
at max voltage there is a probability of the device getting damaged in realtime due to glitches
do clarify what VFD is then more help can be sorted out
means Base Voltage is the Voltage at which we can get maximum output without damaging the motor or its windings
& the maximum voltage is the voltage at which if we continue to run the motor then it definitely would damage the motor & its windings , right ?
as is the same case for base frequency & maximum frequency ???