The last few days have been spent working out the roof opener engineering and details.
As noted above, I chose to go with Sommer 1 HP garage door openers for each roof section. As the roof became heavier and heavier with the addition of the steel roofing and trim, each section's weight was pushing over 550 lbs (248 kg). I began to have doubts as to whether any traditional GDO would work. I contacted Sommer USA, and they referred me to a company – Propel Doors http://www.propeldoors.com/
– which uses the Sommer GDO for large barns and their heavier doors.
I then had the privilege of consulting with Mark at Propel, and he proved to be a tremendous help. He stated that the 1 HP version (Synoris 800) can open a door if it required less than 160 lbs (712 Newtons) of pushing/pulling force to move, but that 60 lbs (267 N) or less would be ideal. He gave me the idea to use a spring weighing device to determine what force it took me to open and close my roof. I used an old bathroom scale pressed against the rafters to get a ballpark figure of 40-50 lbs (178-222 N) for the maximum force required. Thus I could (sort of) breathe more easily - but the acid test would be how it actually worked.
I had further discussions with Mark regarding my ideas to implement the Sommer Direct Drive motor system in a completely different way in which it is designed to be used, but which has proven to be fantastic for the purpose of motorizing my roll off roof: I would separate the control head from the rail track, which feeds power to the motor via the rail track and drive chain, and instead wire the control head directly to the motor. In this way I could mount the rail track directly to the roof rafters, and mount the motor in a fixed position on the wall. So instead of the motor moving long the track and pushing and pulling the roof open and closed, the motor would move the rail track and the attached roof back and forth.
Here’s the Sommer Synoris 800: 1 HP motor carriage on the left, control head on the right, with the circuit board layouts, and revealing the 24 V DC blue and brown motor wires. The wires are attached to leaf-contact springs that make contact with the track rail and chain.