Author Topic: Clockwise or Counterclockwise  (Read 5535 times)

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Yianie123.

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Clockwise or Counterclockwise
« on: February 14, 2015, 11:14:12 PM »
I am assuming that it's best for blade spin to move clockwise, but doe it matter?

frackers

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Re: Clockwise or Counterclockwise
« Reply #1 on: February 15, 2015, 01:18:39 AM »
I depends on which way the mill furls. I think mine precessed off the stub mast 4 years ago. Changing the direction of rotation was one of the things I changed as detailed here:
   http://www.fieldlines.com/index.php/topic,145380.msg987850.html#msg987850

No difference otherwise on direction...
Robin Down Under (Or Are You Up Over)

Flux

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Re: Clockwise or Counterclockwise
« Reply #2 on: February 15, 2015, 04:14:48 AM »
If you make the blades then that answer is correct. If you buy commercial blades then they have to rotate in the direction decided by the aerofoil. The convention with practically all commercial blades seems to be clockwise.

Flux

resonantman

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Re: Clockwise or Counterclockwise
« Reply #3 on: February 16, 2015, 05:34:19 PM »
If your generator is a N S N S N S etc. which illustrates AC , the blade direction is unidirectional. Only until you reach your house or charge controller should you convert to DC. Remember what Nicola Tesla tried in vain to tell Edison. resonantman

Bruce S

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Re: Clockwise or Counterclockwise
« Reply #4 on: February 17, 2015, 09:06:55 AM »
resonantman;
 Since most "blades" are carved with a twist, then my line of thought would be as Flux and Frackers stated, the blades would tend to turn with the twist in mind.

Your statement about unidirectional doesn't make sense. Could you elaborate on this?
Thanks
Bruce S
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MattM

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Re: Clockwise or Counterclockwise
« Reply #5 on: February 18, 2015, 12:12:20 AM »
I thought he was perfectly clear.  Regardless if you mount a blade correct side towards the wind it will still rotate in the same direction.  That makes it unidirectional.

An AC generator cares not what direction it's rotated as it will generate either right or wrong directions.

resonantman

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Re: Clockwise or Counterclockwise
« Reply #6 on: February 19, 2015, 02:19:55 PM »
My statement was intended to be seen as a build the blades as you design. Your absolutely correct about left hand or right hand twist to determine direction of blade rotation. Rob

Bruce S

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Re: Clockwise or Counterclockwise
« Reply #7 on: February 19, 2015, 02:34:24 PM »
Rob;
 Thanks for the clarification.
Cheers
Bruce S
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aerotron

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Re: Clockwise or Counterclockwise
« Reply #8 on: March 03, 2015, 11:04:39 AM »
Whether the blades rotate clockwise or counterclockwise is irrelevant for the HAWT, but not so for the VAWT.  If you are north of the equator, the VAWT should rotate counter clockwise,  and then, if you are south of the equator the blades be rotate thus clockwise. While if you reside at the equator......not sure...in this case I would flush some money down the drain, and depending which way the water rotated, THAT'S the direction the VAWT should go too! 

lifer

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Re: Clockwise or Counterclockwise
« Reply #9 on: March 03, 2015, 01:58:13 PM »
Quote
If you are north of the equator, the VAWT should rotate counter clockwise,  and then, if you are south of the equator the blades be rotate thus clockwise.

Is it related to earth magnetic field or something?!

I live on northern hemisphere and my VAWT is spinning like hell.. in clockwise direction. Actually, I've tested it in both directions (the wing arms are simetrically positioned) but it made no difference at all so I finally choose the most favorable on site condition (there was a small obstacle on the left side). 

klsmurf

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Re: Clockwise or Counterclockwise
« Reply #10 on: March 03, 2015, 03:25:21 PM »
Whether the blades rotate clockwise or counterclockwise is irrelevant for the HAWT, but not so for the VAWT.  If you are north of the equator, the VAWT should rotate counter clockwise,  and then, if you are south of the equator the blades be rotate thus clockwise. While if you reside at the equator......not sure...in this case I would flush some money down the drain, and depending which way the water rotated, THAT'S the direction the VAWT should go too!

I'm no physicist, but this just seems wrong.

Blade direction on a HAWT IS relevant, if it is a side-furling machine.

I don't have a VAWT, but I have an anemometer. If you turn the cups 180 degrees, won't it spin in the opposite direction? Flip the wings on a Lenz and won't it spin according to the airfoil?
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Flux

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Re: Clockwise or Counterclockwise
« Reply #11 on: March 03, 2015, 04:41:27 PM »
Yes you are right. He is referring to the Coriolis effect, but it is so tiny that you might as well forget it except for the old joke about the way the bath water goes down the plug hole,that is why he has a dilemma at the equator.

Flux

DamonHD

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Re: Clockwise or Counterclockwise
« Reply #12 on: March 04, 2015, 12:57:41 PM »
And in fact even the bath-water direction is far more strongly influenced by other factors than north/south of the equator and you should forget about it.  The shape and surface of the hole and surrounding plumbing is more important I think.

Rgds

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topspeed

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Re: Clockwise or Counterclockwise
« Reply #13 on: September 03, 2020, 01:13:40 AM »
Yes you are right. He is referring to the Coriolis effect, but it is so tiny that you might as well forget it except for the old joke about the way the bath water goes down the plug hole,that is why he has a dilemma at the equator.

Flux

There is deeper story to this. I found out that the wake turbulence in stall makes helluva mess if rotating against the Coriolis....there is a study about it. Coriolis itself is a smaller factor as a force.
« Last Edit: September 03, 2020, 09:48:34 AM by topspeed »
These wind turbines must for that reason in a deeper sense be of a timeless beauty, so that they do not in three or four decades hence burden a later generation with a heavy task of removing angular skeletons.....

Ulrich Hütter

Aerodynamics is highly educated guessing, worked out to 5 decimals

bigrockcandymountain

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Re: Clockwise or Counterclockwise
« Reply #14 on: September 03, 2020, 08:08:09 AM »
Ok, so for side furling hawt I believe it has an effect.

I have tried both rotation directions, and i believe for a wheel offset to the right, counter clockwise is better. 

I look at it this way. Picture clockwise rotation and offset to the right.   When the wheel is half furled, the blade at the bottom is coming toward you against the wind.  This makes higher airspeed and more lift. The lift acts pushing toward the tower at the bottom of the arc.

Now gyroscopic precession makes this force pushing at the bottom of the arc act 90 degrees in direction of rotation so the front if the disc gets pushed on, effectively unfurling your turbine.  Reverse the rotation and it helps it furl instead of preventing it. 

I think I see this on my current setup.  It furls only so far, and then no more.  It just makes more and more power.  I manually furl it to keep things in check. 

I will definitely be building my next blades counter clockwise to see if it helps.

topspeed

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Re: Clockwise or Counterclockwise
« Reply #15 on: September 03, 2020, 09:40:39 AM »
Ok, so for side furling hawt I believe it has an effect.

I have tried both rotation directions, and i believe for a wheel offset to the right, counter clockwise is better. 

I look at it this way. Picture clockwise rotation and offset to the right.   When the wheel is half furled, the blade at the bottom is coming toward you against the wind.  This makes higher airspeed and more lift. The lift acts pushing toward the tower at the bottom of the arc.

Now gyroscopic precession makes this force pushing at the bottom of the arc act 90 degrees in direction of rotation so the front if the disc gets pushed on, effectively unfurling your turbine.  Reverse the rotation and it helps it furl instead of preventing it. 

I think I see this on my current setup.  It furls only so far, and then no more.  It just makes more and more power.  I manually furl it to keep things in check. 

I will definitely be building my next blades counter clockwise to see if it helps.

Me too unfortunately the bicycle motor with planet gear does not allow it to rotate anti clockwise.
These wind turbines must for that reason in a deeper sense be of a timeless beauty, so that they do not in three or four decades hence burden a later generation with a heavy task of removing angular skeletons.....

Ulrich Hütter

Aerodynamics is highly educated guessing, worked out to 5 decimals

Scruff

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Re: Clockwise or Counterclockwise
« Reply #16 on: September 08, 2020, 05:11:24 AM »
You generally want any precession effects of a rotating system to tighten the bolts rather than loosen them. Like an angle grinder. I know some alternators are rotation direction biased for this reason but work in both directions.

Adriaan Kragten

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Re: Clockwise or Counterclockwise
« Reply #17 on: September 08, 2020, 06:02:11 AM »
Right hand rotation of the rotor has an advantage if the rotor hub is connected to a tapered generator shaft with no key. If the rotor hub is connected to the generator shaft by one central heavy bolt, this bolt will be tightened if the hub may shift over the shaft because of the right hand rotor torque. My VIRYA windmills have such a connection of hub and shaft and then a right hand rotation of the rotor is required. But aerodynamically, the direction of rotation isn't important. All classic Dutch windmills are rotating left hand. The first Danish modern rotors were also rotating left hand. But at a certain moment, the main Danish supplier of rotor blades made only blades for right hand rotating rotors and from that time right hand rotation became the world standard.

Scruff

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Re: Clockwise or Counterclockwise
« Reply #18 on: September 08, 2020, 03:16:57 PM »
Hi Adriaan,

Nice to find you here.
I have been very impressed with your work.
My first (working) turbine was built partially from your dynohub blueprints. Thank you very much for sharing.



I elected to turn off two LED downlighters instead of fly that after testing. It was the same net power and much quieter.
...that's as far as I got into wind... :-[

gsw999

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Re: Clockwise or Counterclockwise
« Reply #19 on: September 08, 2020, 07:45:22 PM »
My turbine has always turned clockwise, if you are on about the direction to wind the coils it doesn't matter as long as they are just the same, I am building a 12 coil stator 12 volt 36 Turns of 2 strands of AWG14.

https://youtu.be/CCble26azzk

^^ A quick vid of some of the coils I have 3 left to make.

topspeed

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Re: Clockwise or Counterclockwise
« Reply #20 on: September 09, 2020, 12:55:39 AM »
I don't think the HAWT type is much affected by the Coriolis force.
These wind turbines must for that reason in a deeper sense be of a timeless beauty, so that they do not in three or four decades hence burden a later generation with a heavy task of removing angular skeletons.....

Ulrich Hütter

Aerodynamics is highly educated guessing, worked out to 5 decimals