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ryanm
Senior Member

Joined: 25/09/2015
Location: Australia
Posts: 202

Posted: 08:54pm 19 Nov 2015

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Hi Boys and Girls,

New here so nice to meet everyone. Stumbled across this website and now I've got a F&P motor in my shed waiting for me to play with. The site I had in mind has light-med wind throughout the day with several hours of strong wind early at night so I've been looking for a way to maximise the output under the varying conditions.

I've seen the capacitor mod in this forum and it looks like it does a really good job, but frankly I don't have that much experience in analog electronics and I'd prefer something I can understand and fine tune myself. On top of that the journey is half the fun.

I've had an idea to dynamically switch the coil configuration with a microcontroller based off rotation speed to output a voltage appropriate for the battery bank at varying speeds. While the wiring is a little complex, it's not unmanageable. Having looked through this website I can't find anyone that has attempted a similar arrangement so before I go any further I thought I'd put it out there and see if there's an obvious reason no-one has done this that I'm overlooking.

Obviously there are a myriad of design considerations, minimising switching losses, failing into a safe position etc. I'm not chasing any specific technical advise at this point, just wondering if anyone wants to shoot down my idea before I spend too much time on it.

Cheers,

Ry.

rustyrod

Senior Member

Joined: 08/11/2014
Location: Australia
Posts: 121

Posted: 11:47pm 19 Nov 2015

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Seems like a good way to be in the back shed while you work on this project.

I had an alternator that needed the exciter light, problem was the light flattened the battery while waiting for the wind.
I solved the problem with a small wind vane against a micro switch.
When the wind was strong enough it overcame the tension in the micro switch and hey presto the alternator exited.

I like the idea of the rev counter.
Will you fit a separate winding to be energized by the magnets in your F&P rotor or take your signal from one section of your rewired stator?

I could imagine the pulses/voltage increasing to trigger your micro-controller.
Will you use a micro-mite?

"Obviously there are a myriad of design considerations, minimizing switching losses, failing into a safe position etc." Was Edison and any other inventor worried by this?

You may just be the next inventor of the year.

Keep us posted

Always Thinking

ryanm
Senior Member

Joined: 25/09/2015
Location: Australia
Posts: 202

Posted: 12:42am 20 Nov 2015

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I hadn't really considered how to capture the RPM yet, capturing the wave of the first coil seems the easiest way though. Most of my thought so far was into how to actually swap between multiple wirings with solid state electronics. I drew out a bit of a "napkin schematic" and it looks like someone tried to draw a snakes and ladders board on hallucinogenic drugs.

Hadn't heard of the micro-mite until you mentioned it. I would most probably (definitely) use an AVR micro though, as that is what I have experience in.

Downwind

Guru

Joined: 09/09/2009
Location: Australia
Posts: 2333

Posted: 03:52am 20 Nov 2015

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There is a few of us here that use micros and also have built turbines, the reason why no one has taken the path you suggest is the KISS theory.

Once you take a simple workable mechanical design and complicate with electronics then there is no real failsafe, albeit yes you can do it, but why would you want to, as there is little to gain if you get the stator rewire correct to suit your output voltage.

Build your turbine and fly it for a while, then you will start to see how your thoughts will work or likely fail due to mother nature.

The problem with switching methods is should a circuit failure occur (which it likely will) then you can be left with a run away mill.

A runaway is a mill out of control with it trying to self destruct, which they can do very easy.

Switching will likely fail at some point, so where is the failsafe.

Your first design point of view should be to "AWAYS" have the Turbine physically connected to a load (normally the batteries), then divert excess power via switching to other source (normally a dump load)

The bottom line is your theory is good, but flawed due to mother nature.

Go ahead if you intend, but flying a turbine will tell you what I have and far more

Pete.

Sometimes it just works

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