There are two types of AC asynchronous motors: generally, the wound-type asynchronous motors used in factories with relatively large starting loads have slip rings on them, so electric (carbon) brushes (such as lifting, rolling steel motors, etc.) are used, and squirrel cages are used for light-load starting. Type induction motors do not have slip rings, so they do not need electric (carbon) brushes (such as electric fans, washing machines, air conditioners, refrigerators, etc.). DC motors have commutators, so electric (carbon) brushes are used. Hand drills are generally DC motors. The bench drill is an AC asynchronous induction motor; although the general toys and electric shavers are DC motors, due to the simple structure, in order to reduce the cost, a phosphorus-containing elastic brass sheet is used to replace the electric (carbon) brush replacement. The direction device is the wearing part of the electric shaver (the wire package inside the motor is generally not damaged).