Being one who likes to be as self-sufficient as possible, I purchased a hand crank style grain mill. This augmented my weekly baking of Spelt bread. Now you are asking what does baking bread have to do with suppressing voltage spikes on a DC motor? That’s a fair question. Well the first time I tried grinding my wheat berries in my Wondermill grain mill, I quickly understood what they meant by ‘its not the easiest thing to do”.
This grain mill definitely needed a motor! After doing some research on motorizing grain mills I found all kinds of options. However for me, again wanting to be as independent as possible, I wanted to use a 12 volt motor instead of a 120 volt AC motor like most people do. Since my Amateur Radio station is off-grid and powered by 4 golf cart batteries, and a solar panel this seems like a logical choice.
Additionally, I had several radiator fan motors from automobiles laying around, running my grain mill on 12 volts DC made even more sense. This called for a mini road trip to the local industrial surplus shop near me, JDM Surplus to pick up some gears, pillow blocks, and chain.
Here is a video of the completed grain mill running for the first time on a gel cell battery:
As you can see in the video above, I am using a radiator fan motor. Typically these DC motors are a brushed type of DC motor, which due to the commutating of the brushes generates DC spikes that are much higher than the 12 volts that is running the motor. These spikes need to be suppressed so as not to cause damage to sensitive electronic equipment such as my Amateur radio gear, and the solar charge controller.
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