How important is leveling of the Wind Turbine on tower top

[Usman]

I was wondering if an unleveled tower platform would be unfit for a turbine. This sounds like a very basic question but I would doubt if most of the installations are 0-0 leveled. What I mean is that if we place a sprint level on the top of the tower, it would be perfectly leveled in all directions.

In my opinion, leveling is very crucial for the efficient operation of a wind turbine, especially for 3+ KW range where rotors are larger and heavy. Such a rotor would have difficulties in start up (in particular) and thereafter in high winds since one side (the leaning one) may pose heavier to turn for wind than the other.

I would like to know this from the community that how considerable is this phenomenon.

Thanks.

[feral air]

A level and true tower should give you a level top so...I dunno...I'm curious now too.

[TomW]

usman;

Well, if it isn't at least "mostly" level the turbine may not yaw / furl properly. I had a test tower that was erected in haste and was not plumb. The mill always settled with the head one direction because it would try to go to the low side. It is also a good practice to be sure the mast is squarely cut off at the top. This prevents extreme wear from it yawing on a small area of contact.

My general philosophy is construction should be plumb, level and square.

Just observations in the real world.

Cheers.

TomW.

[nothing to lose]

I know from experience, if your tower is not level the heaviest part of the genny will sit to the lowest side. So if the tail is the heaviest it goes to the bottom, if the motor conversion is heaviest it goes to bottom, etc... You have to fight this settling to the bottom effect in order to turn into the wind. So if your genny sits low to the west side and the wind blows from the north you need more wind force to turn the rotor into the wind, your turning up hill! Just like riding a bike, takes less force on the peddles to start out or ride level ground than up hill.

Now if your genny is in perfect balance in all four directions, front, rear, left, right, then you don't have a heaviest side to sit low. It may balance out, pun intended

But most gennies are not in perfect balance in all four directions. Say if you mount your genny 4" to the right of the tower so the wind force on the rotor tries to turn it out of the wind, then that side is heavier. You counter this right side force with weight on the tail to hold the genny into the wind untill it should furl, so the tail is also heavier. What you may end up with then is a heavy right side and rear seeking the downhill side of the tower, a lighter left side and front seeking the uphill side of the tower, the more the tower is not level then the more wind force on the tail needed to seek the wind and turn the rotor to face the wind if wind is from uphill side.

I'm sure most towers are not level at the top. Best guess at level yes, but who climbs a pipe tower 50' or more with guy wires holding it to plumb the top perfectly?

If you get the tower pretty close to level, not off too far, I dought there is much to worry about though. Since it takes X amount of wind to start making power anyway, if your tail is correct and your tower is close to level then the force of the wind against the tail should turn the genny into the wind while still below cut in speeds for the rotor.

 The closer you are to level the better of course, but a really close guess is good enough, and better than climbing 50' or more up a 3" pipe to use a level to plumb top  perfect

[nothing to lose]

Another thing, if using guy wires on a pipe tower. Even if you plumbed perfect when raising, the expansion and contraction of the guys with tempature swings etc... will let you fall a bit off plumb eventually I would bet.

[Flux]

As the others have said, things need to be reasonably level to point into the wind in low winds and more important the furling is gravity dependent and is messed up if the yaw pivot is not vertical.

Normally just making sure that the yaw pivot is vertical by looking at it is good enough, there is no need to go up there with spirit levels. It is the yaw pivot that matters nothing else. If the top tube is not directly in line with the tower you will have to let the tower lean a bit to get the pivot vertical.

Flux

[feral air]

I bet you could use a laser and measure it for level from the ground. I haven't really looked into the consumer laser "measuring tapes" but I know they use high-end (expensive) laser systems for measuring skyscrapers during the build process. If you were really meticulous that might work out better than eyeballing it.

Or you might be able to mount some levels on the top and read 'em with a good rifle scope...

[TomW]

feral;

Sure, a laser would work. But, a much lower tech solution would be a string and a nut.

Tie nut to string.

Hold other end of string in fingers.

Sight the string line next to the tower mast from 3 sides.

Should be real obvious after that if it is near level.

I am lucky, I can eyeball level pretty well with no aids or at least well enough for the mast of a turbine.

The string trick will work from a long ways off and on the ground.

Good luck.

Cheers.

TomW

[Ungrounded Lightning Rod]

And if there's too much wind for the string to hang straight you can do the same thing using a level.  Use the crosswise bubble to get the level vertical when viewed from the sighting direction and you can do the same trick despite a high wind.

[TomW]

ULR;

Good point and something I have done in the past but did not think of.

Thanks.

Cheers.

TomW

[tecker]

Gota be plumb

[finnsawyer]

Since the wind never blows when you first mount the windmill, here's a possible solution.  Attach a long rope and a line with a plumb bob to the tail.  With the mill up, mark a convenient spot on the line.  Then using a transit level (and rod) measure the change in height of the mark on the line as you turn the mill around.  You should be able to measure the change in height of the end of the tail to within 1/8 inch.  While you have to manually step the plumb bob over any guy wires, you also would have the option of adjusting the tension on those same guy wires to level the mill.  You do need some way to remove the rope and line, but I'll leave that to your ingenuity.  And don't give me any static about the transit level.  They're not that expensive.  And a lot of people have them.  I bought one when I started building my second house.  I didn't want to have to borrow one to do the footings.  They're also very useful for putting in ponds or drain fields.

[scoraigwind]

By far the easiest way is to use a level with a magnet in its base.  slap it onto the side of the tower, and adjust the guys until the bubble is centred.  Hanging things on strings is hopeless if there  is any breeze (which there should be).

If in doubt about the straighness of the tower you can sight up along its length, and adjust guys to make it straight.

[finnsawyer]

The tower could be plumb and the mill not level.  One would think that it would be desirable for some line front to back on the mill to be level.  As far the wind always blowing, well that depends on the site, doesn't it?  Perhaps a better choice than a drop line would be a chain, as that will not stretch.  And before someone jumps on me about that, I'd like to point out that surveyors used to use chains for accurate distance measurements.