Dwarven Automatons are found in dwarven ruins, deep underground cities which have been lost to the ages and have been overrun with the Falmer. The automatons were created by the ancient Dwemer to protect their cities, and they still roam the halls looking for unwary adventurers like yourself.
There are 3 types of automatons, each with 3 sub-categories that each have slight differences.
Spiders - small mechanical arachnid-shaped beings that were mainly created for labor, though some of the Guardian level spiders are outfitted with effective defense mechanisms.
Spheres - Fast, deadly, medium health guardians which burst out of chutes in the wall, which are relatively easy to recognize. Can switch to their ball form to get around more quickly.
Centurions - These metal monsters are not something you want to trifle with unless you have a plan of attack or a very high level. Sneak attacks are recommended if possible. In fact, if you have a high enough sneak skill and the Assassin's Blade perk, you can take down of these brutes in one swipe of your daggers. All centurions have the same immunities as the other automatons.