Sounds like your dryer motor is getting hot and shutting down, and taking a nap. The Hi temp thermostat on the bottom of the heating element, and the cycling thermostat on the blower have nothing to do with the machine actually turning the drum... just heat. Now you have a thermal cut off mounted on the upper portion of the heating element, witch is a fail safe if the lower thermostat fails. If that were bad, it also would not shut down your motor, Just no heat. The white thermal fuse mounted on the blower is also a fail safe to prevent dryer fires as well. This is a non resettable part. If it fails your machine will not run at all. I would measure temp out of the 4" vent in the rear of the dryer with no clothes in the machine. It should be no more then 170ish at its highest point in high heat, timed dry. Is your failure consistent with time dry and also auto dry?