Author Options:

Rugged motors? Answered

Does anybody know of a source of motors that are rugged enough to survive long-term* on the surf-line of a beach?  They wouldn't need to survive flying rocks, but saltwater and sand proof would be good.

The plan is to use them in reverse, as generators, so DC is preferable.

*In the first instance, "long term" means "more than half an hour".


Have you considered an electric trawling motor? They're quite a bit larger than the ones you tried earlier. They're meant to be used underwater and run off of a 12V car battery.

Oh, thank you for that suggestion! This idea looks exactly like some of my mental images, but it's $600+ per motor.

I wonder if they can be run in reverse?

I think one like this would be a better solution. They're DC so they should be able to go in reverse if you remove the speed controller. It's plenty powerful enough, and only $150 USD. If you're still in the U.S., you could probably find a used on for less. 

Also, since it has a water propeller, you might consider having water flow through your "chimney" instead of using the air flow. 

Hell, just mount the motor to a dock and point it at the shore.

I've been thinking that the beach environment is just too hostile for an air-turbine.

I have started some rough sketches of a version that uses the waves directly, rather than indirectly, which is why I need more rugged motors.

Cool, I look forward to seeing what you come up with.

Not inexpensive ones. Do the shafts have to be turned continuously, or over a limited angle ? Or put it anotherway, can your concept be executed WITHOUT continuous rotation ?

Preferably continuous rotation - the [rough] concept is a trough (temporarily) laid on the beach, waves wash up and down it spinning a row of "something to spin a motor" (turbine? water wheel?).

Unlike my just-published project, which used air to spin the turbines, I figure that the relatively large energy-density of moving water more than compensates for losses in spin-reversal, and output will just go through a rectifier to provide an irregular DC supply.

I think you are right about the relation water versus air.