for example: 4-poles or 6-poles: which is difference i can see inside motor?
6 pole motor has two more poles than 4 pole motor. .
the formular for speed is 120xfrequency divided by poles. check the speed and the f and you do the maths
In general by looking inside the motor, number of poles can not be known.But while going through the interconnections of the winding coils , the number of poles can be determined.For this you have to findout end of one group of coils and its connection with other group. and thus no of pair of poles can be known.For 4 poles, the connection groups shall be lesser than for 6 pole machine.
yes if you can count the number of coils and interpret the winding configuration a motor rewinder at a repair shop can do this easily put it on a known frequency and measure the RPM - easier
