individual rectified coil question.

[gww]

I have a turbine that has six coils and eight magnets on each of two rotors.  I had it wired star.  It was putting out about 12 volts at 60 rpm.  I took six rectifiers and put the starts and finnishes of the coils to them.  I did not worry about each coil going to each individual rectifier. Some starts may be on a rectifier and the finnish may be on a differrent rectifier.  I would think this would be no problem.  The reason I ask is when I was done I now get about 3 volts at aprox sixty rpm.  I thought my rpm for the 12 volts would go up 1.7 times.  In other words from 60 rpm to 102 rpm.  Couple or questions. 
1.  Do I missunderstand how to rectify individual coils?
2.  Does this mean I need 240 rpm to reach twelve volts?  What wind speed is 240 rpm for 8' blades 7 tsr?
3.  Is part of the problim rectifier loss.
4.  Is it posible that this turbine will work in its current configuration for a twelve volt system?
Thanks
gww

[SparWeb]

Sounds like you've gone from the series-star wiring to the series-jerry wiring.
Like this:



(going from top-left (series-star) to bottom left (series-jerry))
Except in your case, you don't have the pairs of coils together, either.  Now you have split each pair, too, and rectified them individually, too.
Confirm for me that, if the diagram does indeed apply to your case, that you have a rectifier across points 1-4, 2-5, 3-6, 7-10, 8-11, 9-12?

To me you have effectively cut the output voltage (per rpm) by 1/4, as your measurements confirm.

And if you picked any one of the leads coming out of series-jerry, plugged it into one of the ~ terminals of a square rectifier block, yes, it wouldn't matter which one it was.

The alternator could still be suitable for a WT, but that would depend on how its speed (about 250 rpm 12v cut-in) matches up with the size and TSR of the blades.
Moreover, this configuration of alternator has much much less resistance now. 

[gww]

Sparweb
I did no series connections at all.  Each coil is rectified and then all six are run paralel.  My blades are hugh piggot 8 foot tsr 7.  I thought what I was doing was "jerry".  Yours is the first diagram I've seen.  I won't say my blades are perfect but I did my best off Hugh's plans.  I was advised with this turbine to try individual rectified coils but I was't exspecting quite the voltage drop.  Will the 8 foot blades make speed or  will I need to go to seven.  My wheel bearing has a small drag as it is a sealed bearing and I cant remove any grease to loosen it up.  Eight will probly start better if they will make speed.  I ran it open before changing it and it got up to 65 volts before I rewired it.  It didn't seem to be moving much faster then my 48 volt turbines when they get sixty volts.  I'm thinking it might work as it is but wonder if run that way if it will destoy itself much quicker.
What do you think? Try it?
Thank you for your answer above
gww

PS  I think at 7 mph wind the blades would be around 170 rpm.  I think alot of turbines with these blades aim for around 200 rpm cut in.  I wonder if 250 is too big of a rpm leap?

[just-doug]

there are several ways to wire up a stator.each of them will requier a diferent turn count in the coils.if you keep changing  coil winding counts and stator types,you will probley build a pile of stators you really dont like.better to pick one stator type and get the coil turns right before jumping to another type.just my thoughts, just-doug

[electrondady1]

you can rectify individual coils or you can rectify phases(coils in series).
the idea behind Jerry rigging is that individual coils or individual phases give you the voltage you want as is, after rectification.

for instance ,in 3 phase star instead of the output of a single phase having to run through a second phase and  be subject to the resistance of that  phase
so it's not phase output  x1.7 x 1.4 -1.4

its phase output x1.4 -1.4 (x 3)
the out put of the individual coils or phases is run in  parallel.
so you are adding amps in parallel with out adding additional resistance.

[gww]

Just doug and electrodaddy
This was my first turbine.  I have since built more.  This turbine was desined for ferrit mags.  I put neos on it.  I was originally just going to widen the gap and maby put larger blades but thought I would try this.  I could wind a stator that would work better but I am kind of out of the twelve volt stage but don't really want to just throw this turbine away.  I could re wire it star and get 48 volts once in a while but the wind to get it will probly be when my two 48 volts are putting out their max.  Sooo, I thought I would see if I could make it still work at twelve volts.  Is 250 rpm too much to expect out of my 8 foot blades?
Thanks
gww

[electrondady1]

This was my first turbine.  I have since built more.
 
sounds like a serious addiction to me !

i can't help you with the blades
i build vertical mills and they peak at something like 200 rpm, even in a blizzard
I'm always trying to get more amps.
something i learned from both Jerry and windstuff ed,
 there's always another way.
and from flux,
you can get what ever voltage you want at what ever speed you want.
by using the right wire.

[gww]

Electrodaddy
I used wire out of a microwave.  Something windstuffed should understand since I got the ideal from his web site.  I was addicted for awile and made a bunch of solar too.  I still have to install every thing in a year from now.  I am home on vacation during deer season and this is the only turbine I have to play with during the day.  Even with my troubles with it I am having more fun then I would be doing my wifes honey do list.  I got it up so now I think I will wait for some wind and see what happens.  It was flex and ghurd who suggested I might try this.  No blame here as it may take shorter blades and such to bring it home.  I could always wind a stator that matched but I would have to buy the wire and if I do that I will go 48 volts to match my over all system.  I can't wait to tear into the fisher and paykel motor I have as I will probly get to go through these same type issues again.  I have learnt alot from guys like you that are willing to answer my post.  I built this when I thought more volts was better and knew nothing about matching everything.  I am a little smarter but as you can see I am still trying to make a mastake work.  Thanks for the comments.
gww

[Flux]

You originally had 2 coils in series per phase and it was wired star. If you kept the same 2 coils per phase but rectified individually you would virtually have got the delta equivalent and your speed would have gone up by roughly root 3.

Having rectified each coil instead of each phase then you have halved the volts again. That is why your speed has gone up so much.

Yes it does look as though your cut in will be about 240 rpm if you are getting 3 volts at 60 rpm. You may get something below 240rpm if the peaks exceed the battery volts but main conduction will be at 240 and above.

It will certainly work ok in a decent wind area and most likely you will hit cut in at tsr 9 or even 10 with a nominal tsr7 blade as that is the ideal working tsr.

My suspicion is that you will start to cut in about 10mph and in a good wind area that may be a good point and you will have little problems with stall. if you have a very poor wind then you would be better to connect the coils back in pairs but individually rectify the 3 phases ( you don't make a star point and treat each pair of coils  as you have done noe with their own rectifier)

There was a certain possibility for confusion as Jerry sometimes rectified each coil and sometimes rectified each phase. What is different about Jerry's connection is that there is no ac connection ( star or delta) each coil or coil group in the same phase has its own rectifier.

Flux

[gww]

Flux

You originally had 2 coils in series per phase and it was wired star. If you kept the same 2 coils per phase but rectified individually you would virtually have got the delta equivalent and your speed would have gone up by roughly root 3.

Do you mean by root of three that my origional 60 rpm would go to 180 rpm for the same voltage?

I have the turbine mounted in a very poor and low spot.  I may fix this if I can get it close to working properly.  I am in a wind 2 zone so it will never be great.

I am answering this sort of sparotically as I have no internet connection in missouri and have to go to my parents house.

Thanks for the explination.  I don't have a drop of wind to see what I have did so far and how it will act.  If I understand the above statement of yours, It sounds about perfect if I wire the two coils that are in phase in series and individually rectify.

Do the phases, of two coils each for a total of six coils for three phases, need to be to a spicific rectifier or will it be ok to use 3 rectifiers and not worry that each phase be to the exact rectifier for that phase?

I don't exspect much from the turbine and was just trying to keep lawn mower, trolling motor and such topped off.  I also built a ghurd controller and it would be nice to see it in action.

Thanks
gww

[Flux]

Root 3 is 1.732 and is the ratio of star to delta.

Changing a winding with cut in at 60 rpm in star to delta should raise the speed to 60 x 1.73 ( about 103 rpm)

the change to individually rectified phases should raise it to the same value. As you got 240 rpm with individual coils it looks as though in reality that 103 rpm will come out nearer 120 rpm.  There are always measurement errors and waveforms are not perfect.

120 is slow for cut in on a fast 8ft prop so if the 240 you have now is too fast and you need to reconnect I expect you will need to open the gap between magnet rotors to get things up to something near 170 rpm to avoid hard stall.

Flux

[gww]

Flux
If most rectifiers make you lose 1 and one half a volt, does this only hold true if a circuit is made IE; two wires from the coil closing the loop?  If I wired the phases and put one wire to each of the six rectifiers, would this increase the rpm to a higher value due to voltage lost in the rectifiers?  My inclination is it would make no differance but the rectifiers are on the turbine so if it did it would be very simple to accomplish. 

You are right on the measuring of output quite possibly being wrong as I just count seconds while turning the blades.  I measured the three volts at the turbine before wiring to the batteries.  As of now I am on a 16' test tower and only running about 25-30 feet of 12 awg solid house wire. This being the case the 250 rpm may be even wrong and it may take even more rpm to reach the batteries.  When it was wired star It would get to charging voltage and get to one amp and just stay there.  I was waiting for a little wind just so I could see it run before changing it from the individual rectified coils that it is in now but we are sitting at about 5 or less miles per hour with no forcast change in the near future.  I believe I will change it to the individual phase rectification tomorrow and try that.  Maby with the resitance from the turbine to the batteries maby it won,t stall.

Thanks
gww

[tecker]

You need a Bridge on the coils .

[gww]

tecker
Do you mean bridge rectifier or series the coils in phase?
Thank you
gww

[tecker]

From the entries It seems your trying to individually wire the stator to get 12volt cutin . Use bridge rectifiers and place each bridge in series to get your 12volt out . It works Pretty good . Use a cap in parallel to the bridges to hold the power up . Getting 6 wires down the mast is a mess so you'll need an enclosure at the head . Also you'll need to locate the genset close to the battery bank to avoid a power drop on DC line in .
 Do a search for Jerry's posts he is a real proponent of individually rectified stators . I like to run AC to the bank and use cap and diode at the bank but there again that means bringing 4 to 6 wires from the head to the battery bank . I 'll post a circuit of both if you can't find any circuits in the archives  .
Here's what your looking for this does work but there's a half cycle merge between the current that goes through the three bridge rectifiers and the coil charge but if the three stator segments are well matched theyrise together .
I included the star circuit I use on the lower rpm stators (ex bike etc ) the electrolytic caps  hold the star up close to battery voltage .

[tecker]

Most people can see the shorts and ignore them but I corrected the shorts for clarity

[gww]

tecker
Your post is a little above my head.  I did rewire my turbine, two coils in series and then individually rectified them.  I thought I was getting about 6 volts at the turbine at sixty rpm but admit it was a very rushed job and I may not have counted and measured well.  I need two poeple to measure at the batteries and was not able to do so yet.  My rectifiers are at the turbine.  I painted the stator and think I have the coils wired right as it was smooth when shorted and turned.  I hope to know more tomorrow.  I have never used caps yet and at this point don't know which to use or haw to use.  maby latter.  I think with the small wire from the turbine to the batteries  I might be getting really close.  One thing that did suprize me is wired star I could turn it fast enough by hand to get up to two amps but the wind never got past one amp. When I turn it now by hand while hooked to the batteries I couldn't go fast enough to get the amp gage to raise.  It would be interesting if I could get alittle wind.
Thank you for your post.
gww

[Flux]

Yes I really think you need to wait for useful wind before rejecting what you have now, although I am a little surprised you can't crank it fast enough to produce amps with a cut in of only 120 rpm.

Flux

[jlt]

I think you should put it back on the bench . And try to got the start and finish of each coil hooked to the same rectifier .

   Then try to put a amp gauge on the output of each rectifier. and see if you have any output.

   You should be able to light a couple 25 watt bulbs by turning by hand if it is hooked properly.

  Even hooking up wires of a different phase will show some volts.

[tecker]

Post some pictures of the stator connections and your measuring method . It's easy to get crossed up when your starting up the wind can be ify and you have to label every thing to get back on track. sond like you have what you need in star though .

[gww]

Flex, jilt and tecker
I am pretty sure I have it wired correctly for two coils in phase.  coil 1b to coil 4a- coil 2b to 5a and coil 3b to 6a. 

I left the other leads from the coils hooked to the rectifier they were hooked to prior to the changing from the individual coil rectifying configureation.  I just unhooked the leads I needed to reconfigure and caped those wires that are going to the rectfiers that were unhooked.  There are six rectifiers on the turbine and I didn't worry about which ones were hooked to the coils. I might have one wire on each for all I know. 

When unhooked from the batteries I am getting 6.5 volts open voltage at the batteries at aproximatly 60 rpm by just counting seconds in my head.  When hooked to the batteries and turning as fast as I can by hand it bairly bumps the amp gage.  I am standing on the roof of a shed with the turbine on a 16 foot pipe and don't think I get it going as good as when I had it on a 5' stand. 

I could bump it up to two amps when it was wired star.  I have about one more week to mess with it and then I come back again in december for two more weeks.  If it does barely fair when I get wind I will try to get it higher.  If I use 12 awg wire when I go higher it may improve my speed abit more as it will be an even longer run. 

If it still stalls like it was before by getting to one amp and then staying there I may go back to the single coil rectifacation and try that. 

I am dreading taking it apart and makeing the gap wider.  The last one I did that to, I buggered up the treads on one of my allthread that I put it together with. 

I did the math on differrent blade lenght and 9'  tsr 7 would be 150 rpm at 7 mph wind and 10' would be 138 rpm if I remember right.  Both still to high of an rpm. 

I was wondering If I made a slower blade, say 10 to 20 degrees angle the lenght of the blade if this might be a compermise That might help power through this turbines shortfalls?

Tecker,  I may not post pictures as I would have to borrow a cammera go home to take a picture and then come back here to post it.  Its only about nine miles and I am coming here every day to hunt but I may not get it done.  I did bring the wires to the edge of the stator but then I built the stator up at the edges at the mounting brackets and this did cover some of the wires and I painted the stator making the coils harder to see.  I worked out the two wires that were covered with reason by using the star wiring diagram and then ohming the leads of the coils.  I believe I have it right.  I used the old star diagram to get the phases right and then just took the three wires that would normally be connected together and ran them to rectifiers.  I measure having someone watch a very cheap volt meter while I get on the roof and turn the blades aprox. 60 rpm.  I had good wind in the beginning of last week when I checked the turbine while wired in star.  Thats how I knew it was getting to one amp and then stopping.  I was suprized that I couldn't get good readings with just unhooking one side of the battery and puting my leads from the meter to the turbine lead and the battery buss bar.  I had to unhook both turbine leads from the battery to measure it.  Star was giving voltage way to fast and stalling the turbine.

I do wonder if slower/bigger blades would work as opposed to making the gap wider.  I have to make another set for the fisher and paykel so the current blades would not be wasted.

Thanks for taking the time to answer.  I will be waiting for wind to see how it works as it is now.
Cheers
gww

[gww]

Today is the first I got to look at the volt meter while someone else turned the blades of the turbine.  Wired this way the volts don't seem to hold steady but seem to jump around by a volt or more all the time.  It did not do this wired star or when individual coils.  Is this normal with the coils wired in phase and rectified by phase?
Thanks
gww

I also was getting two amps wired star in the wind not one.  I have a 50 amp meter and the first bar is two not one. 

[tecker]

I see where your working now You have the Wind turbine located at a place you like to go and your taking some time with it when your there . have fun with that . Those in between times when the right set up eludes you are somewhat frustrating but you can't escape the learning curve 

[gww]

Ok, I'm back in town.  I took the turbine up another 8 feet to a grand total of 24'.  I know not much and surounded by trees.  I figured it was good practice before for when I put up the two tall towers for my other turbines.

I rectified the turbine individually by phase and added about another 30 foot of 12 awg wire..  I got 14 amps and think it was starting to furl at that point.  Not sure as it is in a terible spot and may have been turbulance and not furling.  I don't think so though.  I have one blade end that has warped just enough to be twisted the wrong way and probly working against the other two blades. 

The wind was 7 to 13 mph on one chanel and on the weather chanel it was 22 mph in the county 9 miles away from me.  I don't know what it really was but seemed fairly strong.  The turbine is much different then my other two.  They spen all the tine even when not making power.  This one takes quite a wind to get it up to speed.  once up to speed it doesn't take that much to keep it going but at the point the wind lets the blades slow to a certain point it slows fast.  there is this speed that it just takes off from or almost stops quikly. 

So it will get going and stay going for a minute to 5 and then will slow and not give anything till the next burst of wind.  I believe this is the drag from the sealed car bearing.

If I put nine feet tsr 7 blades to replace the 8' foot blades do I have a chance of the turbin furling close to where it does now with out changing the 5 inch off set from the yaw bearing?

I will listen to any ideal besides tower hight cause if I go higher I would like a chance for the turbine to work.   What I have did so far has improved it greatly.

Thanks for the previous help.
gww