The main differences among large, medium and small motors are generally determined by the dimensions such as the height of motor axis and the outer diameter of motor stator core, as shown in the table.
Table-Differences among Large, Medium and Small Motors
Nominal motor shaft center height H/mm motor stator core outer diameter D/mm motor frame number
Large motor
Medium motor
miniature motor
Micro motor > 630
355-630
89-3 15
1000
500- 1000
100-500
< 100 is greater than 16.
No. 1 1- 16
10 or less
Note: Three-phase AC micromotor is mainly used for small machine tools, medical instruments and other equipment.
It's a little messy See for yourself.