Motor buzzes on start-up

Dryer motor buzzes during start up. Unit cuts off after 10 mins before dry time completes. Motor won’t start again until cool down, after which I sometimes have to open door and turn dryer drum while engaging door switch. Sometimes unit will run for 20 mins and I when I open and shut dryer door , unit will not come on again until after cool down. Of course it buzzes during start-up , only to shut down after it gets hot again. I have opened unit and thoroughly vaccumed lint from cabinet. There is no venting obstruction, and the drum turns fine .
Do you think the motor is going bad or is this a temp sensor problem or both?? Thanks for yor help!
Angelo