Hi, I'm new, I have a crazy idea and some serious questions.

Hi like I said I'm new here and I've had a lifelong interest in the concept of perpetual motion and over unity (getting more energy from a system then you put in)

First, let me preface this by saying I am not trying to hijack this forum into a debate about perpetual motion so please don't start a fight or ask a bunch of questions which I'd be stupid to answer without a patent.

Due to my interest in perpetual motion, over the last few years I've been researching and experimenting with herons fountains, and other liquid transfer systems. After quite a bit of trial and error I'm convinced I've discovered something and need a little bit of help in trying to build the next prototype

One, I'm having difficulty selecting a turbine style as most of the small generator units I have found were ADS from Amazon Temu or eBay, and they barely contained any information about efficiency, or effective RPM range, plus they don't seem like the most effective designs

Any recommendations for a source with more specialized options preferably retaining the relatively small price range

Two, the information I've turned up on brushed DC motors versus AC motors with a DC rectifier has been confusing due to lack of specifics or claims about the efficiency ranges that seem to conflict

Is one outright better than the other in terms of power generation or is this a case of both operating better in different circumstances under load, and if so which circumstances.

Three, it is my understanding that different turbine styles are supposed to have different effective head ranges. Obviously I'd love to get the most efficient option for my circumstance, which is a bit unorthodox. Right now I'm imagining moving roughly five gallons back and forth through a 3-in pipe every 3 seconds at a constant head height of 4 ft (I know it doesn't make sense to you but please just go with it).

Is there any style of turbine that would be more efficient than 53% under those sort of circumstances? Preferably something saltwater resistant.

Four, I have the option of installing the turbine in an area of the system which would be in constant motion. This raises a few questions because the most efficient styles of turbines are impulse style which aren't supposed to function well under low head conditions.

Is it possible to scale down a pelton wheel or Torgo wheel efficiently, how much would it be affected by different angles of the axis versus slight variations in the head height

Thank you for reading any help would be greatly appreciated.

Welcome to permies, it looks like you're posting in the right place to get some helpful answers, hopefully those will be forthcoming.

From some of your details, wave motion sounds like a match for your conditions, which would actually be a worthwhile area of inquiry. I am not a hydro or electrical engineer so can't contribute more than good wishes to you.

C Paulsen wrote:Any recommendations for a source with more specialized options preferably retaining the relatively small price range

Most of your questions are way too specialized for me to know anything about them. I'm not sure how specialized your pump needs are. If you're thinking off the shelf rather than custom built, I advise taking a look at American Scientific and Surplus. Also, they may be able to answer some of your questions. They have a pump guy, a motor guy, an electrical guy, and probably others who can help match your specs/ needs to their merch, assuming they have what you need. (There may be some overlap; the pump guy and motor guy could be the same guy, for example.)

I don't know if your questions are too specialized for them or not. If so, maybe they can direct you to someone with the knowledge.

Their site is sciplus.com. Their support page has a form to fill out at the top, or there's a tech-support email and a phone number further down the page.

As you come up with a concept, it always pays to refer to basic principles of engineering and physics. For example, when fluids are involved, there will be losses from friction and turbulence. Every conversion of energy from one form to another comes at a price (that's physics). The art is designing a system that is as efficient as possible and can be built from materials at hand with tools you have at a cost you can manage (that's engineering).

It sounds like you wnat some info on Hydro-Electricity

Gross Power = 1/5 * Head * Flow
(sadly this number is usually half by efficicency lost in pipe/wheel/generator/wire/electronics/etc)
Net Power =  50% efficiency * 1/5 * Head (ft) * Flow
Net Power = 1/10 * Head * Flow


What is the head and flowrate of your system
How are you controlling efficiency loss in your pipe, wire, electronics, etc.
It sounds like you are using off the shelf wheels and generators/motors.

Maybe you are looking into tidal stream energy generation, there is alot of cool designs out there. A shroud can increase your flowrate. But even more interesting is the kite designs that folks are using. https://en.wikipedia.org/wiki/Tidal_stream_generator