Okay, I made it through another grape harvest - so now I should have a little more free time. I have been working on the dump loads for my photovoltaic system, with modest success. I have made enough hot water on sunny days to take a hot shower without burning any propane, but I have had to babysit it. I want to have my electronics do all the switching so that I can simply feed power into my batteries, and not worry about overcharging them. I have some parts on order to set up a switching relay to direct power to an air heater once the hot water heater thermostat opens. We will see how that all works out…
Anyhow, I did get a little bit of work done in the shop during a rainy day, and tried building a hand-cranked blower fan out of an old gearbox that I had (off an old label gluing machine). It has about a 10.5x gear ratio
I mounted a shaft on some bearings where the motor originally sat, and fabricated up a radial bladed fan. It is about 4 1/2 inches in diameter, and the blades are maybe 1" tall. I only put on 4 out of laziness, 8 might have been better.
I made a shroud, and brazed that to the plate with the inlet, then bolted the whole thing together. It should probably be sealed with some sort of caulking, but the performance does not seem to be good enough to merit putting more work into it - it just doesnt blow very much air.
I might play around with it some more, but I also found a couple of fans at Goodwill for inflating air mattresses or whatnot, which seems like a much easier approach. I got a 12 volt model and also a more powerful 130Watt AC unit. I remember reading that it is important to be able to adjust the airflow of the blower to match the engine, can that be accomplished by reducing/throttling the opening or exit of the blower, or is it easier to adjust the speed of the fan? On DC I would think fan speed would be proportional to voltage, but can you slow down an AC fan?
I am looking forward to a couple of rainy days to read some more posts.