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non conductors
By electrondady1, Section Mechanical Posted on Fri Jun 3rd, 2005 at 02:28:27 AM MST
liquids and resins

i want to experiment with 1/8 copper tubeing as a conductor i would like to get suggestions on possible non conductive coatins,capable of allowing said tubeing to be used in a coil also , nonconductive fluids capable of acting as a heat sink to the coils, this fluid to be pumped through the stator.

non conductors | 21 comments (21 topical, 0 editorial)

Re: non conductors (3.00 / 0) (#1)
by JW on Thu Jun 2nd, 2005 at 09:19:44 PM MST
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I think its a good idea.

However There are some pro's and con's...

DISADAVANTAGES-

Regardless of high impeadance coolant utilized(for heat transfer removal) there will most certainly have to be a positive displacement electric pump utilized, this means possible amperage req's [exceedance] that such a stator could produce in the first place.

This forced circulation type of methodology would be akin/relative to direct losses commonly associated with energizing "field windings" as such, auto alternators, dont make a good candidate(for wind genny's), but most likely, the same type of parasitic losses from forced cooling (dcvolt pumping)loads would be 10 times worse than any field energization scnario... THIS IS ESPECIALLY TRUE WITH 1/8 COPPER TUBE WINDINGS.

most likely one would do better with high dielectric stregth (linseed)oil forced circulation to the outside of multi-strand windings,in the stator, with a phased zone circulation high flow convection circuit with some sort of raditaor.

Advantages-

The pumping load/force to be applyied to the forced cooling system could be derived from the mill blades itself...

This wouldnt be necessary in the first place, because(sp?) most windmill's dont rotate fast enough to induce hugh hysteriious losses in there stators's/windings.

However, "if" you were driving a load such as a motor does, this forced cooling methodolgy would make sense if the stator were driving such an electric motor. But quite frankly i think its a major overkill on any type of dual rotor type of windmill.

I have developed a 600amp continious solid state "DC" three phase switching array triggered by 6000hz pick ups modulated to operate with a fixed stator.

Im wondering if the standard 1x2x1/2in rectangular[neo] blocks can be procured with 2 separate 1/4in holes cut by water jet, in a centerish position...........

Re: non conductors (3.00 / 0) (#3)
by electrondady1 on Thu Jun 2nd, 2005 at 10:40:50 PM MST
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ultimatly i had a large dia. vawt and miliple gear driven geni's in mind. ive come to the conclusion that if you want big power you must go big. i had in mind, between 12 -16 ft. dia. and 30 - 40 ft tall .i will build an initial 2 ft.dia. unit perhaps a 4 ft dia. as well . i have serious electrical needs. 13kw.s would be a good start. it was mentioned on this board that as much as 50% of the energy generated in the stators is heat. i want to capture that too. a form of co-generation . any way, thanks for the linseed oil tip. i assume i could use boiled lineseed oil? . the configureation i have in mind for this machine would allow me to design in about any rpm range i want . heat could be a factor. i have about 8 gal.s of two part epoxy paint, i have no idea wether it could be utilzed as a non conductive coating on the copper. even if it is non conducive, it might be too brittle to take much winding.

the devise you developed is a delta /star switch ?

there is a company here in canada named jobmaster magnets that will cut neo's to custom configurations with a computor controlled water jet.

[ Parent ]

Re: non conductors (3.00 / 0) (#11)
by JW on Fri Jun 3rd, 2005 at 10:45:44 AM MST
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Hi Electrondady1,

The device I developed is a Mosfet swithching array. Actually its really just a bunch of dc solidstate relays wired in parallel. The trick in developing it was using an input signal of 4volts dc, to activate the solidstate relays, with fast switching speeds this is crucial. The star/delta switch is something different. But the stator wired in star, in my opinion, is the easy way when trying to convert a dual rotor machine into a traction motor. the "electronic commuter" would energize each of the dc phases at the right rotational position, using the mosfet array to switch power on to the phases. And water cooling could really benefit such an motor.

For wind gennys, its my opinion, cooling over the coils(in the stator) would be better for that application. Although construction could be a bit tedious. An alternative to linseed oil (boiled would be fine) is heat transfer fluid. This is a type of oil with a high flashpoint that would resist carbonizing.

I love this board :)

JW

[ Parent ]

Re: non conductors (3.00 / 0) (#15)
by electrondady1 on Fri Jun 3rd, 2005 at 12:51:36 PM MST
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ok, i get it , this is a devise to turn a generator into a motor by controling which coils are energised and at what time they are energised.so a mosfet is a solidstate switch triggered by an electronic signal.

[ Parent ]

Re: non conductors (3.00 / 0) (#17)
by JW on Fri Jun 3rd, 2005 at 03:26:06 PM MST
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That's exactly correct electrondady1.

As you can most likely imagion the star/delta swithing for a genny could be acomplished in the same fashion. Most will point out that mechanical relays could accomplish the same task, and since the swithing frequency(in and out from star to delta) would be like once an hour or something like that, burning up the contact point's in the relay is not a major concern. But it is very hard to compete with a mosfet(solidstate dc relay) in terms of the power req'd to energise it. Compared to a mechanical relay(like a auto starter soleniod) mosfets use way less power to energize. Im very impressed, neat topic.

JW

[ Parent ]

Re: non conductors (3.00 / 0) (#2)
by whatsnext on Thu Jun 2nd, 2005 at 10:04:40 PM MST
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Are you trying to make electricity or heat?
John......

Re: non conductors (3.00 / 0) (#4)
by electrondady1 on Thu Jun 2nd, 2005 at 10:45:06 PM MST
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i want electricity !! man, do i want electricity!! perhapse the two are not mutually exclusive,

[ Parent ]

Re: non conductors (3.00 / 0) (#5)
by commanda (alwynne at unwired dot com dot au) on Fri Jun 3rd, 2005 at 04:06:54 AM MST
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Sorry, but I've just got to ask. Is that 13 Kwatts continuously? Like 24/7? What the *&^%$#@ for?

And if you're not burning it up as fast as you make it, I'd love to see the size of your battery bank.

Amanda

[ Parent ]

Re: non conductors (3.00 / 0) (#6)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Fri Jun 3rd, 2005 at 06:02:28 AM MST
(User Info) http://wooferhound.com

I think that using tubing for coils is a bad idea. That is a lot of large chunks of metal in there and eddy currents will start to cause you too much drag. To eliminate drag you need to use More Smaller Conductors. If you build the stator with pieces of metal as big as copper tubing in it, then it will always seem like the brakes are on when you spin it.

W o o f -={(

[ Parent ]

Re: non conductors (3.00 / 0) (#10)
by electrondady1 on Fri Jun 3rd, 2005 at 10:07:02 AM MST
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hi woof, hope you had a good time in russia, will you post some pic.s? you might remember , my self education in regards to electrical generation is just getting started. i don't understand eddy currents yet. apparently they were a factor in danb's diesel geni's stator because he used copper ribbon instead of wire. another trigger,when windstuff ed posted about a cooked stator. when i research the archives on coil design/conductor usage etc.heat is allways mentioned as a negative byproduct.a limiting factor.isn't the whole process of furling the turbines a result of upper limitations in the generator. it just seemed expiedient to cool the copper as that is were the heat is generated. rather than exotic materials/shapes or inserts in the stator resin.stator heat is not a factor at this stage for me .hey, i'm still dorking around with ceramic mags. but i did see my first neo mag. last week !! a local guy is begining a windmill manufacturing business.he wants to sell me his old experimental mags. 1" x1/4" disks, they shure are strong! the 1/8"od copper tubeing might not be practical but it's only 2 times as thick as 14 gauge wire.

[ Parent ]

Re: non conductors (3.00 / 0) (#12)
by Ungrounded Lightning Rod on Fri Jun 3rd, 2005 at 11:22:00 AM MST
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Eddy currents occur around the lines of force as they pas through the metal.

If you use metal strap edge-on to the field it's like you used wire the same diameter as the thickness of the strap, which is fine. If you use it crosswise to the field you've got an electric brake.

Even though the tubing is very small, hollowing it out and expanding it makes it present more area to the field and thus have more loss than the same cross-section of copper as a wire would have. So you get more losses. It also means you have less wire in a given volume, which means you get less power out from a given geometry and set of magnets. Finally, a narrow hole in the middle means a lot of fluid friction, and thus a lot of power required to pump the coolant.

What I'd do for liquid cooling is wind the coil with heavy wire and embed it in a coolant - or embed the portions of the coil that are NOT in the magnet gap in coolant, and let the thermal conductivity of the wire bring the heat to the coolant. (Most of the heat conduction is done by the same electrons that constitute the electric current you're generating, by the way. That's why good electrical conductors are also good thermal conductors.)

I'd use oil rather than something water-based for coolant. Oil insulates. Water-based coolants would promote electrolytic corrosion through any microscopic defects in your insulation. In addition to the corrosion just sitting there, any slight imbalance in your rectifiers would quickly lead to major corrosion of the wire at the averages-more-positive end of the coil, possibly turning it into metal sponge within weeks. Also: The conductivity of water-based coolants could produce still more eddy-current losses, heating, and electrochemical pathologies as the mag field moves through them.

[ Parent ]

Re: non conductors (3.00 / 0) (#14)
by electrondady1 on Fri Jun 3rd, 2005 at 12:40:08 PM MST
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ungrounded ,dam, i was really hopeing the copper tubing idea would make me a wealthy man and save the planet. the lines of magnetic flux are vertical and are crossing the coil as it moves horizontaly through them, if the long side of the copper strap/ribbon is parallel to the flux lines it causes more eddy currents to occur in the metal. the eddy currents are varyations /fluxuations of electrical energy, that are nonlinear, unuseable, heatinducing and disruptive to the flow of electrons we are attempting to induce?

[ Parent ]

Re: non conductors (3.00 / 0) (#16)
by kitno455 on Fri Jun 3rd, 2005 at 01:40:43 PM MST
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yes. but more importantly, eddy currents are heat producing, and hot wire has higher resistance than cool wire. wire with higher resistance makes more heat. hot wire has higher resistance than cool wire. wire with higher resistance makes more heat....

oh crap. recursion :)

allan

[ Parent ]

Re: non conductors (3.00 / 0) (#19)
by Ungrounded Lightning Rod on Fri Jun 3rd, 2005 at 10:36:06 PM MST
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... the lines of magnetic flux are vertical and are crossing the coil as it moves horizontaly through them, if the long side of the copper strap/ribbon is parallel to the flux lines it causes more eddy currents to occur in the metal.

Think of the magnetic field as a beam of light.

If the beam of light hits a broad surface you get a lot of eddy currents. If it hits a narrow one you get few.

Your wire has to be pretty much at right angles to the field lines one way. So if you imagine you've got a field "shining" onto the table in front of you, your wire might be lying, say, left-to-right and moving, say, front-to-back. So far so good.

But if your wire is a strap you still have a choice: Stand it on edge, or lay it flat.

If you stand it on edge the field "shines" on a very narrow cross-section. Very little eddy currents. If you lay it flat it "shines" on a broad surface. Lots of eddy currents. So when you wind with strip you line it up so the field goes along the broad surface rather then penetrating it - the "standing on edge" orientation in your table example.

Turning a given amount of round copper wire into a pipe makes the surface "seen" by the field broader. So you get more eddy current losses, while the amount of generation remains the same. But with that hollow in the middle you can pack less copper in your slots, so you get less current generated. Lower gen and higher losses at the same time - phoey! You have to cool it a LOT - and use stronger magnets or more of them - to make up for that.

[ Parent ]

Re: non conductors (3.00 / 0) (#21)
by electrondady1 on Sun Jun 12th, 2005 at 06:52:11 PM MST
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parallel is less eddy currents.

[ Parent ]

Re: non conductors (3.00 / 0) (#18)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Fri Jun 3rd, 2005 at 05:43:53 PM MST
(User Info) http://wooferhound.com

To learn about Eddy Currents is real easy. While your magnet rotors are spinning, place a piece of aluminum in the position where your coils would be. Everything wants to stop. You could do the samething with a piece of your copper pipe instead of aluminum.

W o o f -={(

[ Parent ]

Re: non conductors (3.00 / 0) (#20)
by Ungrounded Lightning Rod on Sun Jun 5th, 2005 at 12:01:36 PM MST
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Demo in some electrical engineering and/or physics classes:

Large auditorium.

Big pendulum hangs from the celing over the lecturer's bench. Weight on the end is a disk of copper. On the desk is a very strong magnet (perhaps salvaged from a moderate-to-large magnetron tube.) One of those buggers with a couple quarter-donuts of metal as thick as your neck, growing up out of a strong, flat, metal plate, so the ends face each other across a few inches of gap. Magnet is positioned where the disk would swing through the gap at the bottom of its travel (if it could). Pendulum is held up at one end of its travel by a rope.

Comes demo time. The prof passes his hand through the gap ("Nothing up my sleeve - especially no mechanical watch!") Then he yanks the rope, untying the knot and letting the pendulum swing free. It starts toward the magnet, picking up a bunch of speed in its three-story drop. The leading edge starts to enter the gap.

WHANG!

The disk rings like a gong and stops nearly dead with the leading edge inside the magnet gap. Then it gradually eases into the gap until it's at the bottom of its travel, where it stops.

Eddy currents can produce a LOT of force.

[ Parent ]

Re: non conductors (3.00 / 0) (#7)
by electrondady1 on Fri Jun 3rd, 2005 at 08:23:36 AM MST
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hello comanda, it must be the depth of winter now down under.must you wear a sweater? when it's winter time here it can get very cold. as much as -40c. for you farenhiet types thats -40f. around here you get something called a wind chill factor posted on the weather reports.might not be a factor in australia, thats when a twenty mph wind @ -25c acts apon a surface and drains it of heat as if it were -60c . i have four 500 sq.ft. rental units i must heat. each contain 3 1000 watt base board heaters.add to that, 4 forty gallon hot water tanks, 4 refrigerators, etc. i supply the power through two 60 amp services. 60 amps x 220 volt=13200 watts. a 200 amp service is the modern standard. thats were the electricity will go.

[ Parent ]

Re: non conductors (3.00 / 0) (#8)
by kitno455 on Fri Jun 3rd, 2005 at 08:33:58 AM MST
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you are renting these out? how will your renters feel when the wind stops blowing and they dont have power :) or were you planning to grid-tie? how will they feel about having this monstrosity in the back yard where their kids are playing?

i have an all-electric house myself (heatpump), and it is pretty rough in the winter, especially if the power goes out. my solution? if you want heat, burn something. electric heating stinks. you can build a small woodstove or a grain burner that will cost less to build and run, and will give better heat. you can even build it outside and use an auger to feed it, and use radiant hot water baseboards, and tie that into the hot water system.

best house i ever lived in for that had a huge oil fired boiler that was hot water and radiant baseboard, from one system. never ran out of shower water :)

allan

[ Parent ]

Re: non conductors (3.00 / 0) (#13)
by electrondady1 on Fri Jun 3rd, 2005 at 11:23:56 AM MST
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kitno, yes, i rent the three little cottages out and live in one.i am currently tied to the grid and will not sever the connection, just suppliment my consumpion . i like electric heat ,its's clean and safe and takes up very little floor space. if only it were less expensive. i was hoping to charge the local children money to ride the big wind mill.i am on equal billing so huge winter costs are spread out over the course of the year. there are a lot of charges on my electric bill other than just electrical usage. in effect, i am now paying for the storage of every bit of radio active waste generated since 1950. a central hot water heating system for the various buildings is brobably the best bet for me. i will be digging trenches this summer.there is enough wood stacked up in my yard to heat the entire opperation for a year , and more to come as i have a lot of trees that need work. i have an interest in metal casting and want to build a furnace. i am gathering materials and have a design drawn to create a water jacket on this thing.wood for fuel will be ok for now but is not a long term soution.natural gas runs down my street and i will eventualy hook up but that too is only a short term solution. this year my energy costs will be $5600.oo cdn. dollars . even if energy costs stay the same rate over the next ten years thats like 60 thousand . if energy costs escalate the way i think they will perhaps as much as $100,000.oo

[ Parent ]

Re: non conductors (3.00 / 0) (#9)
by TomW on Fri Jun 3rd, 2005 at 09:05:24 AM MST
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electrondady1;

Kind of off the main topic but if those units share one building one larger high efficiency water heater will run more efficiently than several individual units.

Cheers.

TomW

"Education consists mainly of what we have unlearned."--Mark Twain
[ Parent ]

non conductors | 21 comments (21 topical, 0 editorial)

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