I have an antique Motor? I have attached a picture. It is from the Claxo Company out of Iowa City, IA. There is a label on the back that states, "Caution. Fill motor grease cups every 60 days. Do not allow water in evaporator to spill on motor. Remove evaporator to re-fill". Any ideas on what this is? Thank you.

Since the inlet is tangential, it will produce negative pressure, similar to a dust collector cyclone. My guess would be the motor from an evaporative cooler.

I have a different take on this. While it's true water will cool as it evaperates it also humidifies. I remember those Wisconsin winters where the house got so dry you could feel it on your skin. Our coal furnace had a trough full of water to humidifie the hot air.
Could this be a motorized humidifier? Your thoughts? Tom