Pretty much everything about it is going to be somewhat experimental as it progresses.
This fan was a part of the original construction of a large two story home built in the early 60's. The fan assembly was actually suspended by its four corners with steel rods from the roof rafters. It did not make contact with the ceiling members except by way of a heavy cotton duct.
Anyway, having a 43" blade diameter (housing is 48") and an overall height of almost 24" and given the fact that a weight bearing wall runs through the house, underneath of and parallel to the roof ridge, which by the way only has 3' of pitch in 10', you can see that something different had to done from conventional whole house fan installations. Not to mention the possibility of noise and vibration (remember the original installation?) Not having sufficient negative pressure at the interior of the home to create a cooling effect shouldn't be a problem, but if it is, it should be easy to overcome and still allow natural aspiration to happen. I was actually more worried about to much negative pressure in the attic space.
As for the speed controller, its just a way of controlling amperage use. If, after all is done, I don't need to run the fan at FLA to make the home feel cooler I can turn it down. I was also kicking around the idea of a timer and or thermostat, to turn it off automatically
All over time of course, not all at once. First thing is to build the "squared" copula saddling the ridge and setting the fan and ceiling grate in place and taking an amp reading with the original 1959 Hoover motor. Which is in perfect condition by the way. I want you to know that I looked at new motors, thinking that they would take less amps, mainly because of progressing technologies, this motor is 40 years old, but that exact size motor today still takes 6.6 amps. Something that puzzles me is that the 12vdc motor I am looking at uses 27 amps.
Same 1/3 HP
RPM's 1750 ac, 1800 dc
It would seem that the dc motor is way more efficient.
- X 6.6 = 759
- / 12 = 63.25
Actuall FLA of the 12vdc motor is 27 amps. Thats a difference of 435 watts, more than half, of the ac motor.
