my ipad 3 automatically restarting every after 5 mim

Have you tried a simple reboot yet?

Reboot the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider - let go of the buttons.

If the issue continues to persist, you may need to restore the iOS software on your iPad and then restore from a backup.

Not normal. Take it to an Apple Store for evaluation.

Make a Genius Bar Reservation

http://www.apple.com/retail/geniusbar/

 Cheers, Tom 😉