Author Topic: 60 rpm vawt design shows negative positive results (Read 5364 times)

nicolethomson · « **on:** January 15, 2010, 02:00:55 AM »

Hi all

congratulations to everyone out here. after reading many of the articles, i tried my hands on vawt design from youtube design as well as few articles on howto make PMG,

coils

9 coils, 15Awg 70 windings per coil,

rpm

avg 60 RPM, i used a 72 to 21 gear wheel to see big change in RPM, the max i can count was 60 - 95 rpm's

No rectifier,

Used multimeter (first i tried with analog since it was fluctuating and i couldnt see clear figure i switched to digital)

V- 20m shows +5 or -4

v~ 20 shows +3 to +7 or -2 to -6

2000m shows 25 to 310 or in - symbol figures (dont know what it is)

10A mode it show 2 to 5 or 6 in + or -

Can you tell me how to check the actual voltage/wattage?

i tried checking the magnet placing (north pole south pole positions) with another magnets, every alternate magnet attracts it

the gap between magnet and coils is around 7mm

i tried this measurement at only one set of coil, but i placed all 9 coils in place

magnet

N45 (2"x1"x1/2")12 numbers

thanks

Nic

Bruce S · « **Reply #1 on:** January 15, 2010, 12:55:43 PM »

Nic;

Let's see if I can help out a little in understanding what you're seeing.

By showing that your seeing + & - readings with meter on AC means the coils are working

about a 15V swing I'd guess. This is still correct since the voltage is swinging pos/neg.

The analog meter was working just fine too if the needle was swinging, it truely was following what it was being fed.

Too be able to see it in a much more stable reading and rectifier would be good to attach.

To kinda get a good set of readings, here's what I would try and you'll need two meters hooked up plus a 12V battery that needs charging no matter what size, just so it needs charging, even an old car battery will do at this point.

Attach a rectifier to the output of your mill, the neg wire from the rectifier attach it to the neg post of the battery.

The pos coming from rectifier: hook it to the neg side of the digital meter (even cheap one set meter to 2000mA unless its auto-ranging then just leave the auto-ranging alone) then the pos wire of that meter to pos on battery. This will give you the incoming current. NOW voltage, attach neg side to neg post on neg side of rectifier and postive side to pos side of rectifier.

With the battery still attached you'll be reading battery voltage and that's okay.

To get voltage reading while wind is blowing remove the battery (NOW NORMALLY this would be a BAD idea) for HAWTs due to possible run-away, but VAWTs have a somewhat built in speed limiter

You should then be able to see what the UNLOADED voltage is, current may go to nil since there's nothing going on unless the short-circuit the POS & NEG wires, but I wouldn't do that with the other meter reading voltage.

With battery connected & mill spinning you should see current on the digital meter, if it's not auto-ranging, try a lower setting until it shows something readable.

Alot of things will go into both readings, state of battery, speed of mill & the like, BUT it will get you to seeing stable readings.

The voltage MAY be a big deal as 15V is right at the almost minimum voltage that will show charging for a 12V battery.

Long post; sorry.

Bruce S

nicolethomson · « **Reply #2 on:** January 18, 2010, 06:01:58 AM »

thanks bruce s

Can you please suggest me what kind rectifier i can use.

if possible can you give me a hint on size of it too?

Bruce S · « **Reply #3 on:** January 18, 2010, 08:22:10 AM »

Most any size would be good. BUT I'd go with one big enough to not burn out on a good windy day :-).

If you have a Radio-Shack close by, go there and ask of a good 10Amp unit. These should be fairly cheap in price. These are also found on electric weed wackers and pluggin electric lawn movers. Ac in Dc out, just hook one up according to the lines on the chip.

The ac side will not make a big difference which wire goes to the two ~ line.

Dc should go to a couple wires using the good ole standard of Red for positive and Black for Neg.

Take the wires to something good a solid so you can take measurements without shorting stuff out.

I would worry too much about getting the most expensive one at this point. A electronics resale shop would even be a better place to visit. Tell them what you have going I'll bet they get interested too and will be very willing to point you to the right one.

Best of Luck, come back with some measurements :-)

Bruce S

Hilltopgrange · « **Reply #4 on:** January 18, 2010, 08:57:33 AM »

From your description of 9 coils and 12 magnets I would assume it is 3 phase! If so you will need at least 2 of the standard rectifiers or for simplicity a single 3 phase rectifier something like this one http://cgi.ebay.co.uk/3-Phase-Diode-Bridge-Rectifier-20A-1000V_W0QQitemZ150405622530QQcmdZViewItemQQ
ptZUK_BOI_Electrical_Components_Supplies_ET?hash=item2304dfab02 there are many to choose from just search for 3 phase rectifier. I hope this helps .

Russell

nicolethomson · « **Reply #5 on:** January 24, 2010, 05:54:53 AM »

thanks for the guidance team

Still, i havent' gone through the rectifier portion (apologies mates), but today i noticed 15Amps, 40volts AC per phase (need to verify with you guys in because in AC 10 it reached 40+, if i place the knob at 50, it will move very close by then go back, simultaneously in Amps (10A) it went till 15, then went back to - is the readings i mentioned is right?),

i started uploading the clippings in youtube, will update the link in this post.

please guide me if i do any errors.

nicolethomson · « **Reply #6 on:** January 24, 2010, 06:35:16 AM »

link to youtube

http://www.youtube.com/watch?v=jXjZGD7tUok

and

http://www.youtube.com/watch?v=36II1TIWLao

nicolethomson · « **Reply #7 on:** January 28, 2010, 10:51:27 PM »

anything wrong i have done??

nic

ghurd · « **Reply #8 on:** January 29, 2010, 04:58:41 AM »

Not knowing anything about what you are doing, or what anything else is doing, or how fast the wind is going, or the swept area, or what anything even looks like, its hard to say anything.

The analog meter is volts? Not knowing the scale doesn't help anything.

The digital meter is on the 10A scale? But we can't see the analog meter to know what is happening. If that is sort circuit amps, the short circuit is the problem.

You need to connect it to whatever it will be connected to. A battery? If the open volts was over about 13V, then it would have been charging a little bit.

Connect a battery if that's the plan. Then measure the output.

I have a feeling "anything wrong i have done" is a "vawt design from youtube".

Lots and lots of spinning VAWTs on utube, but not many of the simple ones are shown with an alternator and meter while spinning in real wind, all at the same time.

If this is a single rotor, then that 7mm (0.28") gap from the magnet to the coil is a huge problem. Need to get that a lot tighter to make decent voltage.

G-

nicolethomson · « **Reply #9 on:** January 31, 2010, 11:25:10 PM »

>>>>>>Not knowing anything about what you are doing, or what anything else is doing, or >>>>>>how fast the wind is going, or the swept area, or what anything even looks like, >>>>>>its hard to say anything.

here is the vawt

http://www.youtube.com/watch?v=ycnfIR4vgXQ

>>>>>>>>>The analog meter is volts? Not knowing the scale doesn't help anything.

Yes it is in volts ACV i have placed it in 10ACV

>>>>>The digital meter is on the 10A scale? But we can't see the analog meter to know >>>>>what is happening. If that is sort circuit amps, the short circuit is the problem.

when i connect both together, the device stopped working, so i used to connect it separate. either in Amps or in Volts

>>>>>>You need to connect it to whatever it will be connected to. A battery? If the >>>>>open volts was over about 13V, then it would have been charging a little bit.

>>>>>>Connect a battery if that's the plan. Then measure the output.

not yet connected to a battery or rectifier (yet to purchase a 20Amp rectifier)

>>>>>I have a feeling "anything wrong i have done" is a "vawt design from youtube".

>>>>>Lots and lots of spinning VAWTs on utube, but not many of the simple ones are >>>>>shown with an alternator and meter while spinning in real wind, all at the same time.

sorry mate, i might have not given proper input to get help from you guys

-Nic

ghurd · « **Reply #10 on:** February 01, 2010, 05:36:02 AM »

The problem is the alternator.

The analog meter never shows more than about 1VAC that I could see.

If this is one phase's voltage, in Star it will be about 1.7VAC, which is barely enough to get past the rectifier's 1.4V forward voltage drop.

As it is, it needs to turn about 6 or 8 times faster to begin charging a 12V battery.

The 7mm gap is far to large.

"N45 (2"x1"x1/2")12 numbers" ?

It looks like 12 round ceramic magnets out of microwaves on the top disk.

I will assume there are neo magnets are on the lower disk.

If I can see the magnets from above the alternator, I assume there is a lower disk,

the lower disk is constructed the same way, and there is no return path for the flux.

The magnets must all be placed on a Single piece of iron thick enough to carry the flux on the outside of the alternator between the magnets. 5mm thick steel?

If the gap is tightened it will work better. Possibly twice as well for voltage, and more than twice as well for current.

The iron for the flux return path is vital for decent operation. They must be mounted on iron.

If the magnets are NOT neo, the stator needs changed to something with many times more turns of smaller wire, a smaller gap, AND a return flux path.

I suggest reading and rereading Steven SparWeb's paper "Basic Principles Of The Homemade Axial Flux Alternator".

Pay particular attention to "Magnets" and "Concentrating Magnetic Energy".

Problem: The alternator will not work much until the magnetic fields are properly manipulated, and the coils are in a dense field of flux.

http://www.sparweb.ca/Forum/AXIAL_FLUX_HowItWorks.pdf

G-

nicolethomson · « **Reply #11 on:** February 10, 2010, 09:33:32 PM »

thanks ghurd

here is the updated image/video of http://www.youtube.com/watch?v=g2v4BkbSdOw N45 ndfeb mag's. not able to calculate the rpm since it was pretty fast on heavy wind.

havent checked the voltage etc. need to spend time on it.

--Nic

ghurd · « **Reply #12 on:** February 11, 2010, 05:24:55 AM »

Counting clunks compared to the youtube timer, sounds like about 260RPM.

That is a serious clunk noise. I expect it is taking some power make that noise.

Looks like the disk is not running true, and maybe that is why the 7mm gap was so large.

Getting the disk running more even will help, because the stator can be moved in closer to the magnets.

G-

nicolethomson · « **Reply #13 on:** February 11, 2010, 10:34:55 PM »

you are right, even i noticed it and found it was joint (connecting shaft and rotor) welding is uneven, saturday i will take it to the fabricator/welder and get it rectified.

i changed the gears (150 big gear wheel and 30 teeths in small one) as per the advice from a mechanical engineer.

stator i haven't epoxied it yet, just keeping them in a wooden plate and kept closer to rotor, but what you told was right, the gap is still too much will fix it and post you back,

--Nic

nicolethomson · « **Reply #14 on:** February 22, 2010, 03:13:24 PM »

thanks ghurd

counting clunks compared to the youtube timer, sounds like about 260RPM.

That is a serious clunk noise. I expect it is taking some power make that noise.

now i have rectified this clunk noise issue.

Looks like the disk is not running true, and maybe that is why the 7mm gap was so large.

yes you are right, it was moving up and down, after bringing up 4 screw's (earlier it was 1) now it is rectified.

Getting the disk running more even will help, because the stator can be moved in closer to the magnets

i can see 6-7VAC per phase, is that fine?

ghurd · « **Reply #15 on:** February 22, 2010, 03:47:16 PM »

"i can see 6-7VAC per phase, is that fine?"

It will start charging 12V batteries at about there.

A slight increase in wind speed will substantially increase the output.

nicolethomson · « **Reply #16 on:** February 23, 2010, 07:04:35 PM »

Cool thanks ghurd, let me start trying it this week and will let you know, meantime, i will try to get 20A or 40A bridge rectifier from radioshack and check the battery charging tonight.

--thanks a ton for your support ghurd.

--Nic

ghurd · « **Reply #17 on:** February 24, 2010, 08:56:04 AM »

It takes 2 bridge rectifiers for a 3 phase alternator.

Their 25A is only rated for 50V. Need to keep a battery on it, or keep it shorted without a battery on it.

They have an 8A 400V, which is probably suitable.

G-

nicolethomson · « **Reply #18 on:** February 26, 2010, 07:36:26 AM »

Thanks G-

Saturday i will go and buy the 400V 8A bridge rectifier,

i have a small query, i had 14g and 17g wires, so i tried winding both together (78 turns) thinking that i will get more amp's from 14g and more volt from 17g.

the height of the winding came closer to 2.2cm's and width has come to 3.6inch's. then here instead of single rotor with 12 magnets(2"x1"x.5") 9coils, would love to use 8 magnets 6 coils,

at 260rpm, how much power i can dream off? i tried with a single coil it shows me 1v AC, havent yet moved towards rectifier portion, i would like to finish the stator/rotor position to a final stage and then move towards electrical components, can you please help?

ghurd · « **Reply #19 on:** February 26, 2010, 08:51:04 AM »

I am not an expert on single or dual rotors, that is for certain.

"winding both together"

I have a feeling that will not work out so well.

For a single rotor, Need to keep the farthest turns from the magnet face less than about 1.25cm away.

The turns more than about 1.4cm do more harm than good.

I have a feeling to get a single rotor working under the conditions, the wire would be maybe about #22 to get enough turns in close enough to make voltage.

A dual rotor with 8 magnets 6 coils would probably be similar, maybe 120 or 140 turns of #22?

Those numbers are all guesses. They should be much closer than what you are working with now.

G-

nicolethomson · « **Reply #20 on:** February 26, 2010, 07:30:18 PM »

>>For a single rotor, Need to keep the farthest turns from the magnet face less than about 1.25cm away.

>>The turns more than about 1.4cm do more harm than good.

within 9 inch diameter, trying to accomadate the coils as much as possible, also sometimes feeling like too much of greediness makes it complicated

My guess is if we use two rotor's with 8 magnets, it would help to achive this 2.2cm height to be resolved +(space constraint will also vanish)

rotor1 (8 magnets)

___________

| |1.1cm

2.2cm height of coil

| |1.1cm

-----------

rotor2 (8 magnets)

but here the worries are , will this make it lots of heat generation?

--Nic

nicolethomson · « **Reply #21 on:** March 04, 2010, 11:01:20 PM »

can i try this method?

this weekend, i need to workout the best to attain the goal, please help me/

ghurd · « **Reply #22 on:** March 05, 2010, 05:15:13 AM »

Yes. That is a standard configuration.

If electricity is moving, it is making heat.

I doubt it will get hot enough to melt. The effective swept area looks too small to make enough power to get #22 wire very hot.

Usually, "too much of greediness makes it" not work. Or not last a long time.

The problem with making a self-designed machine for the first project is it is difficult for anyone to help very much.

Making a YouTube VAWT makes the situation worse.

Is this a school project?

G-

nicolethomson · « **Reply #23 on:** March 05, 2010, 04:30:56 PM »

It is for my college project

nicolethomson · « **Reply #24 on:** March 05, 2010, 11:29:12 PM »

ghurd, sorry, might be i am bugging all of you, but definitely not trying tobe greedy, basically i am trying to test the device with 40w incandascent bulb, when it doesnt show up, trying to make many quries before making the staor (havent yet used epoxy- before epoxying i thought of having guidance from you all)

This year on project i am taking it up wind turbine, and thought of using the same at my home also, in balcony i have 20" of wind facing space, so it would be good for me to go behind vawt otherwise may need to face ire's from other flat members too

my apologies if i was pretty much greedy.

ghurd · « **Reply #25 on:** March 06, 2010, 06:35:45 AM »

Greedy for power often makes the alternator not so good.

It does not offend me. Language difference.

Testing with a light bulb is not good.

It is like a shorted output, or like trying to start turning with the brake on.

It can be tested by hand to feel what I mean.

With battery charging, the alternator gets turns up to the battery voltage before any power is removed from the system.

G-

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Author Topic: 60 rpm vawt design shows negative positive results (Read 5364 times)