I bought a used Bodine DC gearmotor and controller off eBay 5 years ago. The nice thing about the DC motor and controller is that it is variable speed, so you can adjust as necessary. At low speed, 1/4 HP is plenty to start up.
Bodine 42A5BEPM-E2 Steel 1/4HP DC Gearmotor (10:1 reducer)
Bodine...