Consider  Honeywell MN7505A2001

Non Spring Return Direct Coupled Actuator, 24Vac, 44 Lb-In Torque, 0/2-10Vdc, 4-20Ma with 500 Ohm Resister, On/Off, SPDT, Floating Control Signal, 95 Second Nominal Drive Time, 0/2-10Vdc Feedback, Declutch Manual Operation, Accepts 1/4″-1/2″ Square or 3/8″-5/8″ Round Damper Shafts, -5-140 Degree Ambient Temperature Range, 5-95% RH Operating Humidity Range, Includes Mounting Bracket, Screws, Shaft Adapter and Water Tight Strain Relief Cable Fittings