How exactly does a turbine convert mechanical energy into electrical?

  • #1

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?
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?
 

Answers and Replies

  • #3
anorlunda
Staff Emeritus
Insights Author
9,137
6,120
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.
 
  • Like
Likes russ_watters
  • #4
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.
 
  • #5
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.
 
  • #6
anorlunda
Staff Emeritus
Insights Author
9,137
6,120
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.

1576093497813.png


And below is a picture of a wind powered phone charger.
1576093612022.png
 
  • Like
Likes dRic2 and russ_watters
  • #7
berkeman
Mentor
59,039
9,137
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?
 
  • Like
Likes russ_watters
  • #8
anorlunda
Staff Emeritus
Insights Author
9,137
6,120
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.
 
  • Like
Likes berkeman
  • #9
cjl
Science Advisor
1,864
439
12mm? You won't make any kind of energy with a half inch turbine. The key with wind turbines is swept area, and you need a decent amount of it to make any kind of reasonable power. What's your application here - what are you trying to accomplish exactly? You could probably charge that battery at a reasonable rate (1hr charge time) with a turbine in the range of 10cm diameter or so, assuming a decent wind source (~10m/s), but that seems like it's probably not the ideal solution for a compact energy source given the unreliability of wind (especially down near ground level).
 
  • Like
Likes davenn and russ_watters

Related Threads on How exactly does a turbine convert mechanical energy into electrical?

Replies
12
Views
9K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
16
Views
6K
Replies
33
Views
10K
  • Last Post
Replies
7
Views
2K
Replies
7
Views
2K
  • Last Post
Replies
2
Views
5K
Replies
72
Views
5K
Replies
13
Views
2K
Top