The hair dryer suddenly stopped when it was used. I'll use it later. What happened?

This fault phenomenon is intermittent false fault, which is the overheating protection of hair dryer.

The common overheat protection of hair dryer is "bimetal thermal protection" switch.

The overheat protection switch is installed on the mica plate bracket of the heating wire and consists of a bimetallic moving contact and a bimetallic static contact. When overheating, due to the different thermal expansion coefficients of the two kinds of metal sheets pressed together, the bimetal is bent and deformed by heating to disconnect the heating wire loop, and the heating wire stops heating, thus playing a protective role.