how we can justify or design the voltage rating of any electrical equipment. some motors are 415 v, others are 11kv, 33 kv, motors. ofcourse the current rating will change as per voltage rating. but at what stage of power rating this voltage will change as any standards.
It was pure depending on the need from market and the possible available power source for these products being sell in future.
Motors are designed for the lowest voltage that is practical based on the wire size required at a given power level. Wire size is an issue from the standpoint of the wire feeding power to the motor and the wire used for the coils inside the motor. Since it is inconvenient for users to have factories and other facilities wired for several different voltage levels, there is a market demand for motors designed for higher voltages than would be necessary based on wire size. Therefore, there is considerable overlap of the motor power ranges offered for sale at any given voltage level.
