How to prevent wire twisting damage?

[AD]

Long time lurker about to start my first wind genny. This board is very helpful, but one issue I have never seen addressed is what to do with the wires coming out of the genny, and how to prevent them from twisting/breaking.

Do you use a slipring or just let them dangle?

I would imagine the constant back and forth rotation of the genny on the pole would repeatedly twist and stress the wires, eventually to the point of malfunction.

How is this problem solved?

[picmacmillan]

hello ad...although i haven't done this yet, i will take a stab at this...they take the wires from the genny and put them into the top of the pipe (yaw bearing),the wire continues down the inside of the pipe to the ground.some have a male and female plug there....every once in a while they will do an unplug and undo whatever twisting has occured over time, inside of the pipe...danb had a post about this a while back...have a good one....good luck on your genny i wll be looking for your results.. pickster...

[Jerry]

Mine just go down the center of the mast. 4 years plus now no problem. Theres not that much twist.

                             JK TAS Jerry

[richhagen]

Had a small gennies up with not that long of a mast, like most of Jerry's they were on roofs, told myself I'd check them ever month or so, and rarely did.  I don't recall ever having a problem with the cables.  I think the cables act like springs and prefer to unwind rather than wind further once they get wound up.  On a large tower with a heavy cable, I doubt you would have much problem with the cable just dangling down.  The cable would wind up one way and then spring like tension from the winding would cause a preferential bias towards the genny turning in the opposite direction.  Just my thoughts on it.  Rich Hagen

[Trivo]

if you check the wind direction you will generaly find the wind comes from one direction and then turns to another and back again very rearly will it go all the way around, here we have an easterly in the morning then slowley turns to the south and west then later the next night it turns back to the south and to the east very rear to the north and if it does it turns back to the west not the east so no 360 deg turning

Trivo

[wpowokal]

One critical thing, buy multi-strand cable it will withstand the/any twisting ie. like welding cable against mains cable.

If your site is relativly clear and there is little turbulance from trees/buildings etc. then the twist is minimal.

regards Allan

[Norm]

   If you have any doubts at all you could make a simple (but large) weathervane, install it near where your genny will be located and let a small rope hang down just as your powercord will be and see if it works okay for your locality, I'm betting that it will average out and you will have no problem.

    The previous answers pretty well cover about  everything on the subject.

                 Have Fun!

                  Norm.

[juiced]

I dont suppose an actual spring of some sort would work well?

  What about 3-4 bungee cable (weak) along the inside of the pipe, opposite of each other? Have the cables going down a smaller, narrow pipe inside...

 

[troy]

Why add complexity and money and effort when there seems to be lots of evidence to suggest that this is a non-issue?  And slip rings have to be exquisitely engineered or they are the weak electrical link in the system.  Hugh Piggot does it with the multistrand cable down the support pole.  Good enough for Hugh, good enough for me.

Puzzled...

troy

[Chiron]

I've been going over the same problem here with cable twist.

In most places there is a prevailing wind or the wind generaly changes in a fairly random pattern or narrow range of directions and I'd just use heavy multistranded cable as has been suggested here and eyeball the situation once in a while.

That's not the case in my area of the country. The Northern Plains of the US (Nebraska, the Dakotas and parts of Iowa and Minnesota) tend to experience a predominately clockwise wind shift. Right now I live in the middle of several commercial wind farms and am on winter layoff from one of them.

In the summer especialy that means the turbines turn to the right about 3 times a week. While that may mean I'd have to go out and untwist my cables once a month or so I also have to take into consideration of extreme cold on the cables (and me) and that my eventual goal is a unit that I can put up and forget for years at a time. On the upside we have class 4/5 wind resource ratings here.

The method the large turbines use is not very practical on a small turbine. They have active yaw control and depending on the turbine in question when they've turned 3 to 5 times in one direction from "neutral" the yaw motor(s) kick in and turn the opposite direction until a neutral position is reached again. Technicaly possible but more stuff to break, more weight.......

What I've come up with is a slip ring design using silver/carbon composite brushes and based on a shaft grounding system for stray currents in large wound rotor generators. I already have some 2" hard brass tubing for the slip rings and 6 of the composite brushes ($35 each) plan to convert the output of the generator to 120 or 240 VAC/60Hz uptower before sending it down through the slip rings at a much lower current than DC used directly for battery charging. Basicaly like the rotor brushes/rings on an automotive alternator but at higher voltage/current and with much better brushes.

If you live in an area with winds like mine and don't want to have to untwist your cables manualy once in a while you can wait until I get my test turbine up. Otherwise follow the advice of the people here with more experience in small wind than me.

Once I start construction on it I'll post pictures, diagrams, schematics and descriptions of what I'm doing. My strong points are Electronic design and power conversion but I definately need to learn from the experience of the people here in all areas of small wind generation.

Any improvements/refinements that come out of the initial designs will be posted here in hopes of contributing to the Art of extracting power from the wind.

.