Torque required for hammer to self right?

[Graw]

something like this?

http://www.ebay.co.uk/itm/24-VOLT-30...AAAOSwBLlVcco6

Just out of interest, what sort of difference in power could you get from one of these (http://www.robotmarketplace.com/products/0-A28-150.html) in comparison to a scooter motor for an axe? Just looking at all my options.