Anyone ever tried buying a ceiling fan from a big box store that says it has a DC motor and trying to run it on DC? I told my wife it was possible so she called my bluff, went to Lowe's and bought two. I reluctantly tore one apart and found that they have 3 wire brushless DC motors. I got on fleebay and found a DC motor driver that would run on our house's 24v DC setup. I temporarily hooked everything up to a car battery and it seems to work. The motor driver has a speed control and a forward/reverse option. I quit working on the project to do the garden while the weather is nice but with some rain in the forecast I am ready to get back on it.
Most older vs and rev ac motors used to use brushed motor, triac to vary the voltage, and sw to reverse polarity between brushes and field. Worked well on upper end of speed, low end bogs down badly. USA were set up for 115 v and you had to get voltage up, but with triac, shut off on o volts, were fairly efficient. large variation in speed with constant voltage and varying load.. DC motors found in Batt lawn mowers, 24 or 48 volts for most part have a lot of uses in greenhouses, etc, often thrown away when batt goes bad. Set to run at full speed and not really designed for long service life.
Update: The fan motor works perfectly until I put the blades on it, then the (Cheap Chinese) controller seems to have trouble getting started. I ordered a new (Cheap Chinese) controller that has a bit more horse power (350w), hopefully it will correct the problem.