# How exactly does a turbine convert mechanical energy into electrical?

## Summary:

What mechanisms and materials are used when a wind turbine converts the rotational mechanical energy to electrical energy within the generator? And is it possible to create a very small turbine for generating small amounts of DC power this way?

## Main Question or Discussion Point

I understand that the turbine drives rotational motion of a low and high speed shaft which rotates within the generator, but how exactly, and with what components/materials does this create electrical energy? Is there a minimum required rotational speed or torque required to generate electricity? Does this minimum vary by size of turbine and generator? Does it vary by load? Is there a simple way to generate or convert this AC current into DC instead? Is it possible to make a very small version of this, potentially around 15mm in diameter of turbine blades?

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berkeman
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anorlunda
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small amounts of DC power
You also need to clarify what you mean small amounts. A science fair demonstration that might make a single LED light glow is a very small amount of power. You could attach a homemade DC generator to a pinwheel and blow on it.

Some people think the power needed for appliances in an RV is a small amount of power, but it is several thousand times more power than a single LED.

A couple questions for clarification...

Are you talking about wind turbines, or water turbines?

And are you familiar with how AC and DC motors work? If you are, then that is a good starting point. If not, you may want to read through the wikipedia introductory articles for background...

https://en.wikipedia.org/wiki/Electric_motor

https://en.wikipedia.org/wiki/Electric_generator
I am referring to wind turbines with relatively lower speeds on a much smaller scale. And I am familiar with induction motors/generators and the like, but I am curious as to if there are any differences or more efficient methods for a generator in a wind turbine that can be used on small scales.

You also need to clarify what you mean small amounts. A science fair demonstration that might make a single LED light glow is a very small amount of power. You could attach a homemade DC generator to a pinwheel and blow on it.

Some people think the power needed for appliances in an RV is a small amount of power, but it is several thousand times more power than a single LED.
Well the "goal" is to attempt charging a 3.7V 350mAh battery with a turbine with a blade diameter of approx. 12mm. Obviously this is very small, so I'm curious if creating a teeny tiny generator would be viable.

anorlunda
Mentor
Well the "goal" is to attempt charging a 3.7V 350mAh battery with a turbine with a blade diameter of approx. 12mm. Obviously this is very small, so I'm curious if creating a teeny tiny generator would be viable.
OK. That is possible if you have enough wind. However, it would be far easier and less expensive to do it with a solar panel. Below is a picture of solar panel phone chargers sold for campers.

And below is a picture of a wind powered phone charger.

berkeman
Mentor
I am referring to wind turbines with relatively lower speeds
Well the "goal" is to attempt charging a 3.7V 350mAh battery with a turbine with a blade diameter of approx. 12mm.
With just one 12mm turbine? Or an array of turbines? Do you know the energy content of low-speed wind in that small of a swept area?

anorlunda
Mentor
My experience with small marine wind turbines on boats is that they produce almost zero power until the wind increases to the range of 12-15 knots. Hence @berkeman 's question about wind speed where you are.

cjl