I'm posting the results of some comparisons I made on three fan assemblies.
I used a water u-tube manometer to measure suction and pressure from each; a digital phototach to check rpm; an Amprobe to check current.
1. NBK 12 blade paddle fan (new)
2. AO Smith squirrel cage 4-3/4" (used)
3. FASCO squirrel cage 4-3/4" (used)
I also swapped out the squirrel cage for a 4.44" 9 blade paddle on the AO Smith.
I used a water u-tube manometer to measure suction and pressure from each; a digital phototach to check rpm; an Amprobe to check current.
1. NBK 12 blade paddle fan (new)
2. AO Smith squirrel cage 4-3/4" (used)
3. FASCO squirrel cage 4-3/4" (used)
I also swapped out the squirrel cage for a 4.44" 9 blade paddle on the AO Smith.