Winding Coils Piggot's Method Vs. Dans Method ?

[JerryD]

Am very undecided on which method to use Piggots or Dans !  Piggots Method uses 12 Mags 10 coils with 80 trns #15 and produces 5 phase 12v.  Dans Method uses 12 Mags and 9 coils with 35trns 2paralell #14 and produces 3 phase 12v.  Which method is better for Southern Ohio where the winds are mostly low and need to produce most power out put on the lower end approx 7-10 mph.  Please elaborate as I would like to

make a good performing  Gen on first try.  Thank You JerryD

[Flux]

Either method will produce virtually identical results. Just choose one method and stick to the instructions. Trouble comes when people change things.

Hugh I think largely chose his method to keep it as simple as possible for those with no electrical knowledge. Coils are all the same there are no inter coil connections to worry about the phasing of each coil, it uses thin and easily handled wire. Every step is covered in detail so there is no excuse to go wrong.

If you know enough to know what you are doing from Dan's information it will produce identical results. With Dan's method you have the option to bring 3 wires down and keep the rectifiers off the tower if you prefer.

Flux

[picmacmillan]

i agree with flux...i  would advise you to pick one of those and do not deviate at all, or i think you will have trouble...i did my own thing , and although i know it is going to work very shortly, i went the hard way..i did learn alot in this process, but it gets very frustrating early...you can almost double the cost of building one of these with just a few mistakes, such as the wrong number of windings, wrong thickness of stator, and the wrong size magnets(too small being the most common mistake)...

 I have built 2 real nice machines so far, and both will get going, but i have to battle by myself as they are unique in most ways to others.....this was not my intent by the way, it was that i made a mistake and tried to fix it, therefore making more mistakes....do like flux says and copy one to a tee and you will not only learn as you go, but you will save some real grief in the process...pickster

[scottsAI]

The two methods seem so different how can they say they are the same?

I will simplify how things work a bit.

With multi phase AC, and a multi phase bridge rectifier.

You understand only one phase is supplying voltage to the battery at a time.

Lets pretend each phase is independent of each other. (Not technically correct...)

Voltage out is = Turns * Flux lines * K

We will assume the constant, K is the same for both machines. Therefore ignore.

The 5 phase with 10 coils, gives us 2 coils per phase.

The 3 phase is 3 coils per phase.

I assume the coils are in series. Is that correct?

Flux lines is the number of magnets over a coil. (simple remember:)

The math becomes:

3. phase: 35 * 3 * 3 = 315
   
5. phase: 80 * 2 * 2 = 320
   
   

They are just about the same.

Where they will differ is at high wind speeds. The 5 phase is #15 gauge

wire vs the 2x #14, the impedance of the 2x #14 is much lower so will be

able to provide more power. Assuming the magnets are up to it.

The 5 phase does have a slight advantage, more voltage peaks per RPM,

which reduces it effective impedance, not sure if it makes up the for 2x

#14. But for slow speed may be a slight advantage.

So follow the other advice!

Have fun.

[Flux]

The 3 phase design has 3 coils in series per phase. The 5 phase has only one coil in series but two are in parallel via the rectifier.

The line voltage of 5 phase is 1.9 compared with 1.73 for 3 phase.

The end result is similar.

Flux

[Flux]

JerryD

Previously I only commented on the alternators, I have realised that Dan uses a 10ft prop and this will have more low wind capture than the 8ft that is standard on Hugh's design.

If your winds are really low and you choose to use the 5 phase method you should consider the larger prop that Hugh mentions in this link.

http://www.scoraigwind.com/axialplans/update.htm

Flux

[hvirtane]

Hi,

in principle you can get

about the same results

using either of these

methods.

But I think that it is

actually better to go

directly to a real

three phase system as

Dan is using.

Hugh's method is a good one,

if you only want to copy

a ready made thing,

but to understand the positioning

of the coils and their relationships

with the magnets it is better

to study the basics if the three

phase system.

If you'll make a three phase

alternator you can later

change the connections

to wire the alternator

either in delta, star or

rectify all the coils separately,

if that is the best for

the voltages you got.

It is not so difficult at all.

Please see my diary and

really excellent posts

and pictures by

"Electric Ed"

about the positioning

of the coils.

The easiest method to make

a three phase alternator is

to make the relationship

of the magnets with the coils

to be 4/3.

My diary pictures:

http://www.fieldlines.com/story/2004/6/2/163021/1860

- Hannu

[Jerry]

HI Hannu.

Reading through your diary you sugjested rectifying each phase sepratly will produce the best power. I agree with you.

I'm modifying a GE ECM motor. It is 3 phase. It has 18 coils. I've done somthing simular befor on a GE ECM. I wired 2 coils directly accross from each other in sires then wired these 9 coil groups in star. This time I'll wire the 9 groups to there on and sperate full wave bridge as you've sugested.

I'll make the bridges from seperate 6 amp diodes as befor. It will be another porkypine arangement. The first one works very well. I did the same thing to the F&P.

                            JK TAS Jerry

[DanB]

do you mean this Jerry?

Do you guys really think this is going to be better overall?

I agree perhaps if the machine is in Delta, and we have lots of parasitic currents flowing around due to mismatched or misplaced coils, this might solve those problems, but it doesnt make sense to me to rectifiy our phases seperately like this.

In the picture above, a good deal of the time (especially at or near cutin) - there will be no current flowing through the conductors in the stator.  (at cutin, most of the time most of the wire in the stator is doing nothing).

If we rectify in a more standard fashion, we will have current flowing through all the conductors all the time - this is one of the big advantages to having a multiphase machine, and by rectifying each phase seperately we don't realize that advantage.

Its why 3 phase motors are usually smaller, and more efficient - because they make better use of the conductors within them.  When you rectify each phase seperately - you loose that advantage.

[Gary D]

Dan, I think Jerry is trying to get the best use out of thinner wires by cutting the resistance per coil set. He sacrifices the very low end(cut in) in return for better preformance at higher speeds (less heating in the motor). Jerry will hopefully explain better than me... If heavier wire were used like in a motor rewind, this wouldn't be needed? You are choosing your wire gauge (for cutin speed and max output)so I don't think there would be any benefit in changing your windings to thinner wire size. Not worth 2 cents (ignore if you wish!) Gary D.

[DanB]

Hi Gary - yes, I see that, and it probably is the best way to go with his conversions, because its basicly a 2 phase system there, and the phases are not matched.  So in that case, using rectifiers on each phase seperatley makes sense.

But in a normal 3 phase alternator, our best bet is to wire it into Star, or Delta (probably Star) - and if we rectify each phase seperately we're not making best use of the copper in the alternator.  If we rectify each phase seperately, we basicly have 3 single phase alternators and lose half the benifit of having a 3 phase machine - that benifit is that, if we wire it conventionally and use a normal 3 phase rectifier, then we have current flowing in all the conductor all the time.  If we rectify each phase, any time the voltage is below cutin - there is 0 current flowing in that phase so were wasting copper and space in the alternator.  Thats my understanding anyhow... and my understanding seems to change frequently so who knows ;-)

[Flux]

Dan I have done some tests on this in the past to see if it would solve the delta problem with circulating currents. As far as I can see it behaves exactly as delta. It does remove the circulating current below cut in, but as soon as the rectifiers conduct it behaves as delta complete with the losses.

I agree that any improvement from this method must come from a better match there is no other virtue.

Flux

[DanB]

I would think that at higher output levels, we would realize somewhat lower resistance if we wired in Delta, because current from one phase can flow through the other two phases.  I would expect at low output levels there would be virtually no difference because at low output levels the slightly higher resistance isn't making much difference..

Another drawback in my mind with rectifying each phase like this..  it forces us to put the rectifiers on the tower top.  I think it's handy to keep that stuff on the ground.  Then we can also have our stop switch between the rectifiers and the wind turbine which seems safer.

currents flowing between the phases in Delta is the main reason it makes sense to wire in Star I think, although that can become tedious at low voltages where we have to use really thick wire.  Although even at 12 volts it seems managable for a 10' machine, and I don't think it's practical to have 12 volt machines much larger than 10' diameter.  

[Jerry]

Hi Dan.

This topic was discused one on the old board. I think Tom W understude my perception of this?

Its a matter of phasing. 3 phase is exactly that. 360 degrees devided by 3. Each set of coils is producing voltage but they are all 120 degrees apart.

In single phase if you take any 2 coils coils and wire them in sires you get get twice the voltage. In a 3 phase system take any 2 coils and wire them in sires the voltage woun't be double. It will be less because while one coils voltage maybe at the peak of its wave and highest potential the coil it siresed with will be 120 degrees behind or ahead. They'll never both or even all 3 will never be at there highest voltage potential at the same time.

We moved our stereo store to a diferant building. They old buildind had 3 phase service. If you mesured accross the 120v line you would get 121 to 124 volts.

If you measure accross any 2 of the 3 you get 208v not 242 to 248 volts. This is because of the things I've talked about above.

I wish I had a blackboard and this group in front of me. It would be easyer to explane.

Once each coil or coil phase group has been rectified to dc there is no diferance in the dc. There for each dc output is at its highest potential and can be wired in sires or perelell.

I understand that the voltage will be higher when wired in normal 3 phase star but there is still that 120 degrees diferance between coils that alows some potential power to be sacrificed.

Its as though you have 3 people lifting something very heavy. The first guy lifts with all his stringth the as he begins to withdraw or let go the second guy steps in then when he gives up the third guy jumps in. They are 120 degrees apart.

My contention is lets get these guys lifting the heavy load together.

I realize there will be higher voltage in the normal 3 phase star but if the coils were wound with more turns of slightly smaller wire to compinsate all of the power potential could be relized.

As it is with normal 3 phase some of this power is lost to the cosmose?

I know when I wired a converted with NEOs GM car alt this way as a wind generater I got it highest output.

I just think more thought should be put into it befor dismissing what I'm saying?

As fas as I know I've gotten the highest power out from a F&P doing it this way?

Phase timing has merrit and should be looked at. A few expiriments I'm sure will shed some light on the subject?

When you wire normal 3 phase star just think how much power would go up if the coils were in phase.

To see the effects of things being out of phase just wire one of your speakers in your stereo system out of phase with the other and listen to the diferance. Thats 180 degrees out of phase. In your 3 phase generater it would be only 120 degrees out but the overall preformance still will not be optimall.

As far as power reduction each phase will produce its normal amount of power as allways. When combining the powers of all these coils and phases at the ac stage power is lost do to these coils being out of phase or in sinc with each other.

Combine the power after the rectifier when the power is DC and then this power is on the same page there is no longer a power robing out of phase condition.

I relize that a coil turns coun't and such must be rethought a littel but at the same time more power can be extracted from the same alt.

If I'm all wet on this subject shoot me down, correct me. Show me how coils out of phase produce better power than coils in phase.

                         JK TAS Jerry

[TomW]

Jerry;

AMEN

Cheers.

TomW

[Jerry]

Thanks Tom. Your vote of confidence just brought a big smill to my face.

                       JK TAS Jerry

[hvirtane]

Hi,

for some reason my yesterday's

comment seems to be lost.

I only wanted to say that

I'm quite completely in agreement

with Jerry.

Further: there are some

more experiments

we know about this issue.

'Windstuff Ed' made sometime ago

some experiments with different

connections, star, delta and

rectifying separately. The last

option seemed to give the best power.

Also Alfred Forbes in his well-known

book 'Homemade Dynamo' is telling

the same as Jerry and Ed. The best

power came out by rectifying separately.

In my opinion, if suitable capacitors

are used with each phase, connecting

the separately rectified phases in

series, will also give the best voltage?

I'm still in India and cannot read

or comment this list everyday.

- Hannu

[Jerry]

Thanks Hannu.

I'll keep testing these ideas till there is  more solid evidence. If I'm wrong I'll just be as happy. All I want is to get the best power out for the work that goes into building a machine.

                    JK TAS Jerry