DIY DC Powered Box Fan Conversion

Here is a quick talk-through on how to convert an AC box fan to DC power. Not only does this save power (can you say green?) by eliminating the 20 watts needed for the field coils in an AC motor, but it also makes it more portable as it will run off of 12/24vdc. A stock box fan pulls 55 watts on high speed, this unit now pulls 35 watts at same speed. It can also go even faster then stock motor and the speed is fully adjustable instead of just 3 presets. All you need is a donor box fan, a DC cigarette power adapter, a DC motor from an electric scooter (I used a 24v 350watt), and a DC PWM motor controller. The specs for the motor controller are: Working Voltage of 12-36VDC Control Current: 10Amps PWM Frequency - 20+ Khz You can find these motor controllers on ebay. Mine was purchased for $10 shipped from china. 1. Take off the front and back grates. 2. Pull off the fan blade assembly from the AC motor as it's usually just friction fitted to the motor shaft. 3. Remove AC motor from frame. 4. Build two legs from straight 1-1/2" slotted steel and bend into a U shape. This will serve as legs to counterbalance the now back heavy fan, and also the fan mount itself. 5. Externally mount the U bent slotted steel to the existing two vertical arms that the AC motor was mounted to previously. 6. Mount DC motor to top of U bent slotted steel, and shim horizontally and vertically so when fan blades are attached, they are centered in fan box. 7. Attach fan blade assembly to DC motor (may have to custom engineer a solution as these motors usually have reverse threaded shafts). 8. Install PWM speed controller in upper corner by hole for speed selector and verify clearance from rotating fan blades. 9. Wire up input power (with properly rated fuse) to PWM Controller, output power to DC motor, and mount PWM Controller potentiometer in old speed selector switch hole. background music provided by MitiS under creative commons free use license. Check out his work at his soundcloud page:   / mitis   ------------------------------ Mad Electron Engineering with Rick Cullen is a participant in the Amazon Services LLC Associates Program, ​an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com FTC Disclosure Statement: Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these. ------------------------------ Links in description are affiliate links. My videos are for educational purpose only. Information is subject to change/update at anytime. ------------------------------ Check out my Amazon store which will have a list of all the products I review and use in my projects: amazon.com/shop/madelectronengineering