AC asynchronous motors are divided into two types: generally, wound asynchronous motors with large starting load in factories have slip rings, so they use electric (carbon) brushes (such as lifting and steel rolling motors), while squirrel cage induction motors with light load start do not have slip rings, so they do not use electric (carbon) brushes (such as electric fans, washing machines, air conditioners, refrigerators, etc.) DC motors have commutators, so electric (carbon) brushes are used The electric hand drill is generally a DC motor, and the bench drill is an AC asynchronous induction motor; Although general toys and electric shavers are DC motors, due to their simple structure, in order to reduce costs, phosphorus containing elastic brass sheets are used to replace the electric (carbon) brush reversing device. They are vulnerable parts of electric shavers (the wire package in the motor is generally not damaged)