REANIMATION OF THE SWAMP THING
Part 1: 2011
The nationwide heat wave has given the rest of America a taste of a normal Phoenix summer. Fahrenheit 110 or 115 is common. In the Celsius world (everywhere but the US) that would be in the 40’s. Our heat is something even Republicans don’t mind sharing.
Though we’re used to it, July is not a good time for a swamp cooler motor to quit, as mine did. Most coolers use a standard type motor, varying in horsepower and one or two speeds, but all mounting alike, running the blower with a belt drive. Almost any hardware store sells them.
Mine is different.
It was made by Hampton Bay, a company that mostly produces ceiling fans. They decided to get creative. Then they lost interest and discontinued it , as well as any replacement parts one might need. The motor was smaller in size, and drove the blower directly. It also spins in the opposite direction.
After a fruitless search for a motor with that specification, I decided on my favorite course of action: improvise.
I bought a standard cooler motor and attached the blower drum to its shaft. Due to the reverse spin direction, it had to go on the opposite way, which meant that the securing allen setscrew ended up next to the motor, inside the blower drum. The only way to tighten it was to use a long-shafted allen wrench through a space between blower blades, with a squint and a flashlight.
That problem solved, the motor had to be mounted on the opposite side of the blower shroud to blow the right direction. I constructed an improvised mount out of an old heavy steel computer case (it had originally housed one of my IBM 8088 PC’s). Wish a little experimentation (well, maybe a LOT of experimentation) the motor hung solidly in place.
Turned on, my new motor blew even harder than my old one, which was no surprise, since it was twice its size. I happily relaxed in front of its cool breeze.
My carefree coolness lasted until I got my next electric bill.
I have had other coolers using the same size motor or larger, and they didn’t use nearly as much power. The problem, I concluded, is that this one was turning the blower directly, but the normal configuration is by a belt drive, with a small-to-large pulley, reducing the speed, which allows the motor to rotate with less effort. The faster blower speed was adding more resistence, causing the motor to draw more power.
I formulated my plan for next year, to reconfigure my cooler with a belt drive. Parts for that standard system are readily available at the hardware store.
PART 2: 2012
After meditating and procrastinating on this project all winter, I was mentally prepared to begin the project as April temperatures approached 100 F. (about 38 C.). The standard cooler shell is roomier inside, with space for the motor an top of the blower shroud. On my more compact cooler, the motor would have to be mounted externally, with an opening through which the belt could extend to the blower pulley.
This I saw as an opportunity to correct a design flaw in the standard cooler. Placing the motor inside the evaporative chamber subjects it to high humidity, a mist of calcium-laden water droplets that encrusts the motor with deposits, which shortens its useful life. A better design would place the motor in a separate compartment, outside the corosive environment.
The first step was to place the blower on a shaft with a pulley at one end. I bought 2 spiders, Y-shaped mounting supports with a shaft bearing in the center. The smallest shaft is 3/4 inch in diameter. The motor shaft, which the blower had been mounted on, is 1/2 inch, which meant that I needed to turn a 1/2 inch hole into a 3/4 inch one. A few hours of rather noisy reaming with a dremel did the trick.
Cutting the belt hole in the thick steel shell was a bit much for a dremel’s cutting disk. I had to use a larger cutting wheel and my drill. Then I constructed a motor mount from some of the many pieces of wood and metal piled in my back yard. I could have bought a standard mount, but I like to improvise. With a bit of finagling and adjusting, I had the motor turning the blower smoothly. I covered the motor with a heavy steel box to protect it from the occasional desert rain. Wired and reassembled, it was ready for a trial.
It worked even better than I expected. It was just the right airspeed, and it ran quieter than it ever had; quieter than other standard coolers as well. The cooling effect was excellent. A few minutes in front of it made me chilly.
Time will tell whether I have solved my power-consumption problem, but I’m optimistic about that, too.
–Cosmic Rat May 21, 2012.