Shaded Pole Induction Motor - Cooling Fan

This article and video contributed by Ron Walters

A number of these shaded pole motors are sold without a fan. The motor will run much cooler and will probably last longer if a fan is installed on the long rotor shaft. I have recycled fan blades from old computer tower cooling fans. A hub can be machined from metal or plastic with a small setscrew to attach the blade to the rotor shaft.

The direction the motor is turning will determine the correct blade configuration to use. You want the fan to blow air across the shading poles in order to have cooling efficiency.

Sometimes small fan blades can be found on eBay. This particular fan appears to have been intended for one of those wall outlet air fresheners.

I machined an adapter hub to fit on the rotor shaft. I wanted to remove the internal plastic webs of the fan so the hub could be inserted.

I installed a round wood block in the lathe chuck and used a small drill bit to accurately center the fan against the wood block. Hot glue was applied to the back of the fan.

The hot glue will securely hold the fan in position as long as the machining operations are done slowly and gently.

A mill was used to cut away the center portion of the blade...

...providing room for a boring bar to gently remove the internal structure of the fan, and providing a snug fit for the adaptor hub.

Gently remove the fan from the wood block and clean off the glue. I decided to cut a clearance hole in the center of the fan so the setscrew portion of the adaptor would pass through the fan. I used a little hot glue to secure the fan to the adaptor hub.

Without a fan the shading poles will get hot enough to immediately burn your finger. Using this small fan the shading poles still get hot but they remain within an acceptable limit.

Other projects by Ronald Walters:
Reversing a shaded pole

Making wooden U-joints

Planetary gear drive
Wooden roller chain
Pin gear experiment

More projects by Ron Walters

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