It sounds like your motor is failing, and the overload protection is kicking in to shutoff the motor.
You may just have a build up of lint and other debris, so disconnect it and use this manual to open it up and clean it out, and be sure and check the dryer door if the airflow goes through it as lint builds up there most of all. If after cleaning it up you still have the problem it probably means replacing the dryer motor.
http://frigidaireservicetips.com/pdfs/488_3.pdf