Author Topic: Active Pitchcontrol  (Read 331810 times)

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mbouwer

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Re: Active Pitchcontrol
« Reply #726 on: June 10, 2017, 06:13:57 AM »
Teeth removed. Now it looks more similar to a lamination for a direct drive.
I am now going for 144 new slots.

mbouwer

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Re: Active Pitchcontrol
« Reply #727 on: June 11, 2017, 05:23:01 AM »
Idea: Drilling 144 holes ( dia 4 mm ) on pitch circle 321 mm ( pitch 7 mm )
+ on the rotor 321 magnets 20 x 3 x 2

mbouwer

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Re: Active Pitchcontrol
« Reply #728 on: June 12, 2017, 04:58:55 AM »
you don't have to stick to the +/-2 rule, but below a ratio of 5 poles for 6 slots the winding factor drops off and copper losses skyrocket

How should I apply it in this configuration?

Adriaan Kragten

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Re: Active Pitchcontrol
« Reply #729 on: June 12, 2017, 05:24:28 AM »
The number of stator poles must be dividable by twelf, so that is correct for 144 stator poles. So you can use 142 or 146 armature poles if you follow my rule that the number of armature poles is two more or two less than the number of stator poles. If you have 144 stator poles, 72 full coils can be laid. So 24 coils for each phase. The coil sequence then is: 12 coils U1, 12 coils V1, 12 coils W1, 12 coils U2, 12 coils V2 and 12 coils W2. All 12 coils of one coil bundle have the same winding direction and are connected in series. Be alert that the 12 coils of coil bundle U1 is connected such to the 12 coils of coil bundle U2 that the voltages of both coil bundles are strengthening each other.

If you don't follow my rule, so if you take for instance 140 or 148 armature poles you will get the coil sequence: 6 coils U1, 6 coils V1, six coils W1, six coils U2, six coils V2, six coils W2, six coils U3, six coils V3, six coils W3, six coils U4, six coils V4 and six coils W4. If you take 138 or 150 armature poles, you will have three coils in a coil bundle and you will have eight coils bundles for each phase.

joestue

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Re: Active Pitchcontrol
« Reply #730 on: June 12, 2017, 10:05:06 PM »
you don't have to stick to the +/-2 rule, but below a ratio of 5 poles for 6 slots the winding factor drops off and copper losses skyrocket

How should I apply it in this configuration?

by deciding to cut your new 144 slots, the only reason i can understand why you decided to do so, was because you wanted to stick to the traditional 3 slots per 1 pole, or 48 magnets.

but you can do anything between 128 and 142 magnets, as well as 146 to 160. you can go as high as 176 magnets (magnets means poles in this context) before the winding factor drops below .9

110 to 124 is also possible but the winding factor is .9 to .93. not super good, but still reasonable.
note that some of the wiring possibilities are rather complicated.
https://www.emetor.com/edit/windings/


because you've decided to cut your own slots i would make the magnet pole count as low as practical to keep the frequency low, due to eddy current losses in the laminations.
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

Adriaan Kragten

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Re: Active Pitchcontrol
« Reply #731 on: June 13, 2017, 03:52:22 AM »
I also don't understand why you removed the existing stator poles and want to go to 144 slots. The remaining width of the stator is rather small and there is only little space for making of the 144 slots. So there will be only a little space for the copper of the winding and therefore the maximum power you will get out of the generator at a certain rpm will be much lower than for the original stator stamping. Mounting of the winding will also be more work. The winding may look more like a scaled down version of the winding of a big windmill but I expect that the power you get out of this generator will be disapointing.

mbouwer

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Re: Active Pitchcontrol
« Reply #732 on: June 13, 2017, 04:27:20 AM »
Before I start drilling I definetely like to discuss more options.

Joestue,
 
You think I better drill 48 slots diam. 8 mm / pitch 21,3 mm and tooth wide 13 mm?

Adriaan,

Why not give every tooth a coil?

mbouwer

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Re: Active Pitchcontrol
« Reply #733 on: June 13, 2017, 05:30:23 AM »
Have just completed and painted the axle. Now making a matching hub.

Adriaan Kragten

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Re: Active Pitchcontrol
« Reply #734 on: June 13, 2017, 08:36:38 AM »
Before I start drilling I definetely like to discuss more options.

Joestue,
 
You think I better drill 48 slots diam. 8 mm / pitch 21,3 mm and tooth wide 13 mm?

Adriaan,

Why not give every tooth a coil?

If you give every tooth a coil, you have the wires of two adjacent coils in one groove. So a coil can contain only half the amount of copper than for the option of a full coil around only half of the teeth. The power generated in two half coils is the same as the power generated in one full coil so I see no reason to favour the double number of half coils.

If you have a coil around half of the teeth, and if one coil is opposite a north pole, the adjacent coils are also about opposite to north poles. So all coils of one coil bundle have the same winding direction. If you have a half coil around each tooth and if one coil is opposite a north pole, the adjacent coil is about opposite a south pole. So adjacent coils must have a different winding direction.

I suppose that all coils of one coil bundle are wound outside the generator and will therefore have the same winding direction during winding. So if the coils are mounted, you have the turn half of the coils 180 degrees to realise an altenating winding direction. This is rather complicated, especially if you have a lot of coils in one coil bundle.

mbouwer

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Re: Active Pitchcontrol
« Reply #735 on: June 14, 2017, 11:31:24 AM »
Is'nt it an advantage the coils fit better winding them on the tooth? (instead of using a coilwinder)

The hub.
« Last Edit: June 14, 2017, 11:40:13 AM by mbouwer »

Adriaan Kragten

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Re: Active Pitchcontrol
« Reply #736 on: June 14, 2017, 03:09:55 PM »
Winding of the coils outside the generator is the general practice for asynchronous motors. I think that the main reason to do so is that the winding thorn can rotate very fast and that all wires are good in parallel to each other which results in the maximum amount of copper in a groove. Asynchronous motors use rather thin wires and have many turns per coil so the coils are very flexible and even round coils can easily be mounted in straight grooves. But for certain low voltage generators with thick wires, one sometimes uses winding robots which lay the winding directly in the stator stamping.

Lying of the winding directly in the stator stamping has the following disadvantages if it is done by hand:
1) The stamping is rather sharp and the wires can easily be damaged at the edges of the stamping.
2) The wire will not be straight in the groove and the wires will cross each other so the copper density will not be very high.
3) One can very easily make a mistake if one counts the number of turns per coil.
4) It takes a very long time to lay a full winding.

But it is possible and I have laid the winding of my first 12-pole PM-generator made from an asynchronous motor this way. But I made two special brass parts with which the coil heads were guided from one groove to another. It took me more than a complete day to lay the winding of a 12-pole PM-generator frame size 112. Your stator stamping is very short and may be winding by hand is then an option if you have enough time.

hiker

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Re: Active Pitchcontrol
« Reply #737 on: June 14, 2017, 07:25:35 PM »
Just wrap a little tape around each tooth..toss a peg in the empty slots that sticks out aways ...only need one or two pegs..for what ever size the hole in the coil is...then just wrap the wire around..as even as you can...pull pegs when done with that coil then do same with next....if your wave winding..then of course you will need more pegs...practice with a piece of string or old wire....really dosent take vary long to knock one out.....made a few truck alt conversions in that way....
WILD in ALASKA

joestue

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Re: Active Pitchcontrol
« Reply #738 on: June 15, 2017, 12:55:02 AM »
at this point, i would say wind every other tooth for a concentrated pole winding. its half the complexity, and you can probably get more copper in it than winding every tooth. also there is less chance of a short between two coils or between two phases.

because you have to start over with cutting slots, the number doesn't really matter. pick the number of magnets you can place on the rotor for the most number of magnets, ideally the ones you already have. if they are 10mm wide, then go with that number, 15, etc, 20mm, etc. or if you have imperial magnets, 3/8th, 1/2", 3/4" or 1" wide magnets. pack them close together and use that number.

once you have the maximum number of magnets on the rotor for a practical and available width of magnet (that is, use what you already have, and or use the magnets that are cheaper per cubic inch), then choose the slot count that makes sense.

if you go back to that site i link to repeatedly, you need to choose a pole count and a slot count that makes sense. winding factor should be as high as possible. so should the least common multiple, higher = less cogging torque. also, avoid the choices that force you to use a 2 layer winding. on that website, 2 layers for concentrated pole motors means you have to wind every tooth.


I still tend to think that the magnet length to width should be approximately 1:1. meaning if your lamination stack is 20mm deep, then use 20mm wide magnets. this dimentionless ratio seems to hold across a lot of different types of machines, but we see exceptions everywhere.

for example, the 100MW direct drive hydro turbine generators that are 20meter/60foot diameter. the poles are a foot wide, all 120 of them, (or whatever number it is) and 4 feet deep/thick. perhaps in an ideal world the generator might be made to be 40meter/120foot diameter, and the poles 2 feet wide and 2 feet deep. the air gap would be the same 4 square feet, but the electrical length of the copper windings would be reduced from 10 feet to 8 feet. diminishing returns at this point. clearly they can't make the generator that large diameter, so you make it deeper instead.  the weight would be the same, but the air gap velocity would be double, so you would multiply the windage losses by 8, but divide by two for the reduction in depth. so windage losses would be 4 times higher, for 20% less copper losses.


so, i'd use whatever magnets you already have. i don't think the pole count is significant until you discover what your eddy and hysteresis losses actually are.
« Last Edit: June 15, 2017, 01:09:47 AM by joestue »
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

mbouwer

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Re: Active Pitchcontrol
« Reply #739 on: June 15, 2017, 09:09:33 AM »
Windmillfriends,

Trying to build this generator it is very nice to be guided by people who are more knowledgeable than me.
I wonder what I can do for others who also want to use windenergy.

mbouwer

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Re: Active Pitchcontrol
« Reply #740 on: June 16, 2017, 05:49:06 AM »
To easely work on the generator, and because I have to make it anyway, I want to create a setup on a yaw bearing.
The hole is to mount the drive of the bearing.

mbouwer

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Re: Active Pitchcontrol
« Reply #741 on: June 17, 2017, 06:10:59 AM »
Pivot.


mbouwer

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Re: Active Pitchcontrol
« Reply #742 on: June 17, 2017, 11:11:36 AM »
update: 4 leg lattice test set up.
now I want to shape the basic generator rotor ring.

mbouwer

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Re: Active Pitchcontrol
« Reply #743 on: June 18, 2017, 05:08:49 AM »
Basis for the rotor magnet backing ring.
The outer diameter is going to depend on the magnet thickness.

mbouwer

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Re: Active Pitchcontrol
« Reply #744 on: June 19, 2017, 05:21:31 AM »
The lamination after drilling the 10 mm. slots.
Now I have to polish them en replace the coating.

I wonder what kind of coating I can use here.

mbouwer

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Re: Active Pitchcontrol
« Reply #745 on: June 21, 2017, 08:27:20 AM »
It's a bit of a struggle and a lot of ancillary material is needed.
But how else can I get a suitable lamination core?

mbouwer

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Re: Active Pitchcontrol
« Reply #746 on: June 22, 2017, 10:27:14 AM »
Made a testcoil ( 0,5 mm ø  / 6 m. lenght )
Now I want to ream the inside diameter of the lamination core.

joestue

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Re: Active Pitchcontrol
« Reply #747 on: June 22, 2017, 08:36:54 PM »
stone the burs down with a coarse oil stone, bake the laminations at 500F/300C till they have an oxide layer.

its not critical to reduce the air gap to zero, the 48 sided polygon (i presume that's what you have) is close enough to a circle..
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

mbouwer

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Re: Active Pitchcontrol
« Reply #748 on: June 23, 2017, 08:39:46 AM »
By letting rotate the core on this test stand I wil try to become a nice inner diameter surface.

mbouwer

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Re: Active Pitchcontrol
« Reply #749 on: June 24, 2017, 05:34:44 AM »
Blades flange is now bolted to the stand.
The core can rotate freely to polish a nice and even inside diameter.

mbouwer

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Re: Active Pitchcontrol
« Reply #750 on: June 24, 2017, 11:07:50 AM »
Flattening the surface and machining the inside diameter nicely circular shaped.
« Last Edit: June 24, 2017, 11:19:53 AM by mbouwer »

hiker

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Re: Active Pitchcontrol
« Reply #751 on: June 24, 2017, 12:07:19 PM »
need some plastic inserts for each hole...I lucked out on some motor conversions and was able to reuse the original ones...when I ran short I made a few from plastic place mats...
WILD in ALASKA

hiker

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Re: Active Pitchcontrol
« Reply #752 on: June 24, 2017, 12:15:41 PM »
Make the inserts a bit longer then the slots..so when you bend the wire around it won't rub on the sharp ends of the lams...test each coil after winding for shorts to the lams..nothing worse then to have wound a stator..only to find out a coil is shorted out..!
WILD in ALASKA

mbouwer

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Re: Active Pitchcontrol
« Reply #753 on: June 24, 2017, 03:33:41 PM »
Thought of setting up a test rig now.
1 coil and a dummy rotor with 2 magnets ( thickness 10 mm )

mbouwer

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Re: Active Pitchcontrol
« Reply #754 on: June 25, 2017, 05:15:57 AM »
In addition to the 3 adjustable spokes I now also have added 3 fixed spokes.

mbouwer

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Re: Active Pitchcontrol
« Reply #755 on: June 26, 2017, 04:15:58 AM »
Ajustable dummy rotor to fasten and test various types of magnets.

mbouwer

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Re: Active Pitchcontrol
« Reply #756 on: June 27, 2017, 05:54:58 AM »
Test with 2 coils: wire 0,5 mm  lenght 6 meter
                         wire 0,14 mm lenght 2 meter

With the three stacked magnets thickness 6 mm I get 0,1 volt at 100 r.p.m.
With the round magnets thickness 10 mm both coils show 0,5 volt.

How to proceed?
« Last Edit: June 27, 2017, 06:05:02 AM by mbouwer »

joestue

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Re: Active Pitchcontrol
« Reply #757 on: June 27, 2017, 02:47:16 PM »
for a concentrated pole design you need all of the magnets installed to get volts/hz out of a single coil without using a spectrum analyzer to isolate just a single frequency's magnitude.

and since they aren't all in phase, you will need to multiply the voltage you get out of a single coil, by the winding factor, which for a 40,44,46 magnet, 48 slot machine is 0.96 to 0.95

your 2mm thick magnets are about half as wide as they need to be, so you can take them and arrange them nn ss nn ss nn ss. a 2mm thick layer of magnets may be enough, 4 would probably be better. do you have enough magnets on hand for a 2 mm layer arranged nnssnnss? for a 40, 44 or 46 pole machine you would need 80,88 or 92 magnets.

they do need to be radially aligned perfectly far as i know. probably doesn't matter if one is out of place, but if half of them are a degree or two bunched together, you could have a lot of cogging torque.

you don't have near enough room for copper to effectively utilize the 10mm thick round magnets, doesn't mean you can't use them, its like installing a 400hp engine in a geometro. it doesn't weigh enough to effectively use the hp, but you can still burn the wheels out. but so would a 100 hp engine.
My wife says I'm not just a different colored rubik's cube, i am a rubik's knot in a cage.

mbouwer

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Re: Active Pitchcontrol
« Reply #758 on: June 28, 2017, 09:19:57 AM »
48 slots.
So I can buy 46 magnets 20 x 18 x 5
They fit on the outer diameter of the rotor.
« Last Edit: June 28, 2017, 11:44:35 AM by mbouwer »