dryer won't stay running

The dryer will start but won’t keep running.

A model number may help others help you.
http://www.appliancepartspros.com/modelnumber_locator.aspx

Also a better description of what is happening would be helpful.

If the dryer comes on and runs for awhile, and then shuts off, and you have to wait a little bit before it will turn on again, it is a motor!!! Tom http://www.applianceeducator.com