In our case, the vacuum just stopped working right in the middle of use. My wife was using it when it happened. When I came home we both looked at it and concluded the roller and lights worked when they were supposed to, bu the vacuum motor itself was not running. Reading this wiki , the motor thermostat seemed like the right answer, but it had been down for well over an hour and should have cooled down by then.
We then UNPLUGGED the machine (it had been plugged in the entire time). Went to dinner, came back, and it worked just fine. Going to clean the filters so it doesnt have to work so hard.