Author Topic: Help needed on a Breezy type grid tied induction turbine  (Read 1328 times)

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Kyle

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Help needed on a Breezy type grid tied induction turbine
« on: December 22, 2017, 05:15:30 AM »
Hello to everyone. I am new to the forum. I have been reading and learning what I can over the last month. I am new to wind turbines.

My project is a small turbine(750 watt) with a 3 phase/220 volt motor and a 10:1 gearbox. I have been reading about the Prairie Turbines “Breezy 5.5” and am trying to do something like that only smaller. Their web site is shut down and my attempts to contact have failed thus far. I was hoping to find one of their books which may explain some of my questions.

My current hurdle is the wireing of the 3 phase to the single phase grid. I read that the Breezy did this without a converter. Could someone with knowledge of this explain how to wire my motor to accept the single phase 220 v?

paara

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #1 on: December 22, 2017, 07:47:55 AM »
You are trying to connect you 3 phase wind turbine directly into a 220v grid, without an invertere?

JW

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #2 on: December 22, 2017, 11:17:30 AM »
Post some pictures so we can get a better idea of what your trying to do. Also it may not be possible for what your trying to do.
: with what you have.

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #3 on: December 22, 2017, 01:54:19 PM »
Thank you for the reply. Here is a picture of the project.  I don't have a picture of the wiring block but it is a standard 3 phase/220 volt setup with 3 leads. I can't tell if it is delta or star setup as yet. Hopefully I can figure it out when I open it up. I think I have the wiring bypass figured out. It sounds like adding some capacitors to one of the 3 phases will trick it to think the single phase is 3 phase. My 3 wires will be, 1 - 220v +, 2 - neutral, and 3 - 220v+ through capacitors. I understand I will be sacrificing 60% power to do this.  I will be pulling it down and experimenting this weekend -weather permitting.

george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #4 on: December 22, 2017, 06:48:27 PM »

I believe the wiring setup you are looking for is called C2C.
It's a pretty common way to convert 3 phase to single.

One leg from the motor goes straight through. The 2nd leg has one  cap and the third leg has 2 caps of the same value or 1 cap of Double the value. you can wire them 1-2, 2-3 and leave 3-1 open or direct connected. Use 440V caps or the highest you can get.
You can tap off any 2 legs you want back to AC.
The trick will be working out what the value of the caps is. For a 750W motor I'd guess something around 10-15Uf.

Hard to say because what I have dealt with is constant speed and the problem with this setup would be the motor has to be over synchronous ( nameplate) speed in order to generate. In low winds the thing will - motor. You will be using power not making it.

I can't see how you would prevent the thing becoming a fan not a generator in low wind without some sort of controller or relay etc.
Not that my lack of knowledge means much but If I am right, could be the reason this site closed down... because their idea/ product didn't work!

You can't use a Diode or you'll loose AC and the thing needs to be phase locked in order for this to work.  You could maybe use a relay powered by the generator. once it came up to speed ( voltage) it would engage the AC.  Problem here is when the wind stopped, the relay would probably drain the windings making it necessary to flash them to get some residual magnetism before the thing would generate again.
An SSR may overcome this. 

You'd need an arduino or something to sense the speed and which way the current was going.
Only other thing I can think of is using a PWM controller. Not sure if it would work but they are $3 on fleabay so if it didn't work and you blew the snot out of it, hardly any big deal.

I was thinking what would work would be a solar grid tie inverter. You'd only need a  little one so the cheapest you could buy used would be the go. Again, rectify the output to DC then feed it into the inverter. The problem I see here would be on a turbine there would be some oscillation as the inverter tried to find the sweet spot and loaded the motor up and down. If the motor dropped below sycronous speed it would loose field current and  drop out. On 3rd thoughts, the inverter would have a voltage cutoff so once the power got below 90-150V, whatever the threshold for that particular inverter was, it should drop out and not de saturate the residual flux in the motor windings allowing it to come up to speed and energise again.

Without some sort of current limitation though ( another controller) I think the things would be ramping up and down all day.

The other thing to be aware of is this will NOT be a 750W generator. In practicality you'll  get around 300W off the thing if you can drive it hard enough. After that the voltage in the windings in the motor will get too high and you'll get overheating.

Normally this sort of setup is used for Driving a motor off an engine. You get the engine driving the motor near synchronous speed, Connect the AC then bring the engine up to speed at which point the motor starts generating. The power generated is controlled by the engine speed and the value of the caps.  Higher caps make more power at lower speed and vice versa within limits.

Be interested to see if anyone else here knows how to prevent the thing becoming a fan without the use of a controller.

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #5 on: December 22, 2017, 08:49:13 PM »
Thanks for your input. It will take some time for me to sort through it. Tons of great information.  I do plan on a controller. Jondecker76 posted http://www.fieldlines.com/index.php/topic,138266.msg917173/topicseen.html#msg917173

Where he made a controller that does that. I am hoping he was successful and has a product available.

I am also worried about creating one huge fan. I hope to spin it up and when it is close to sync speed, (ala hall sensor) cycle off the power and let the wind bring the rpm above sync before powering back on to generate. Use an anemometer and relay to only turn it on when wind speeds are of value.

I was wondering what kind of output I could get. Is the 300 watts due to the conversion of 3 phase to single with the capacitors?

george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #6 on: December 22, 2017, 09:19:36 PM »

So seems I was correct, one DOES need a controller for a setup like this.
The people you first mentioned must have used one.

The 300W output is more due to the fact you are using a motor as a generator instead of a motor.
I have read claims of 75% generation but that tends to be on white papers and real world accounts tend to tie in with my own at closer to 50% or a fraction less.

There are a number of factors in using a motor as a generator that account for the reduced output but it's a while since I read up on it and I won't go into details because I'll surely use the wrong term and get lambasted for it. :0)
Guess all you need to know is it is inefficient because you are using something in a way it was not designed for and that's the price you pay for a cheap generator. 

Wouldn't be anything to stop you using a 2KW motor and getting 1000 watt or maybe 1100 the same way as long as your blades are big enough to drive it in the prevailing wind.

SparWeb

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #7 on: December 22, 2017, 09:39:03 PM »
Sounds challenging, certainly a learning opportunity.
The controller Johndecker worked on sounds like the thing you need.  I don't remember an update following that project.  It will take a bit of know-how with motors to make the hook-up work.  As George puts it, "you are using something in a way it was not designed for". 

Bear in mind you will also need the encoders, the resistance load, and then... <ahem> some way to convince your electric utility that you know what you're doing and that the output power will be suitable for whatever feed-in plan they sign you up for.  This is the biggest hurdle you face.  Given that the electric utility is a powerful "gatekeeper" on a grid-tie installation, making them angry leads to all sorts of unpleasantness.  Be careful and make sure you know you will be accepted before even asking them the question.  Be prepared to play by their rules.  Accept that they are paid to keep everyone safe and running efficiently, and everything below a megawatt is "small fish".
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

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george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #8 on: December 22, 2017, 10:39:13 PM »
 

Bear in mind you will also need the encoders, the resistance load, and then... <ahem> some way to convince your electric utility that you know what you're doing and that the output power will be suitable for whatever feed-in plan they sign you up for. 

This is a significant point IF you are worried about having everything approved etc.
 To me, the current pricing of solar makes wind a rather expensive proposition if there is any alternatives.  For some there isn't a lot other alternatives and cost is not the issue as much as have or have not.  Where solar is available, it is far cheaper, more developed and easier to get approval for.

For experimentation purposes and learning if that's your base goal, maybe look at building the same sort of thing only replace the blades with a small Diesel engine and run it on veg oil.  Everything else will be the same so you can still learn most of it.

With Solar panels, no one pays any attention to them. Unless you are on land, just the erection of a wind tower will also put the wind up your neighbours as well as the local authorities.  The tower itself incurs significant cost  and it's a bit hard to hide the things if you are trying to fly under the Radar. I would imagine most places less than decent acreage would have strict rules about the construction of such towers and the approval process would be a cost and drama in itself.

joestue

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #9 on: December 22, 2017, 11:29:30 PM »
i think you have a good chance of doing this if you wire your motor for 138 volts delta, and if you run a 150 volt battery bank/load.  this might be as low as practically possible.

Take a vfd and find where it senses the line voltage. then replace the igbts with mosfets. run the vfd from a small 120vac or 120/240v isolation transformer if 150vdc is too low a voltage to get it to turn on.  this is only to supply the vfd with power through the existing flyback transformer.

run the mosfets directly to your 150 ish voltage battery bank/load. you may be able to get by with 100, AAA nimh batteries.

so now you need to program the vfd for a non linear volts per hz curve. you can then further manipulate the actual volts/hz output by manipulating what the vfd thinks the line voltage is. you may be able to get an additional 2:1 ratio over what the vfd can be programmed for.

then you need an arduino or some other means of telling the vfd what frequency to output to the motor. there is both an optimal volts and an optimal hz for both the rpm and the torque going into the motor. this could be analog, lots of vfds will accept a 0-10v input.

due to the cubic nature of the wind power, and the torque on the generator follows windspeed squared.. the volts per hz will need to be proportional to the wind speed assuming the slip frequency is set to a constant value.. it doesn't have to be.


you can then send the 150vdc into a grid tie inverter
« Last Edit: December 22, 2017, 11:37:59 PM by joestue »

joestue

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #10 on: December 22, 2017, 11:44:41 PM »

The 300W output is more due to the fact you are using a motor as a generator instead of a motor.
I have read claims of 75% generation but that tends to be on white papers and real world accounts tend to tie in with my own at closer to 50% or a fraction less.

figure a 1/2 hp motor is the smallest induction motor you can get any power out of at all, as a generator at nameplate volts per hz. once you drop the volts you can get power out. the reason for this is typically a 1/2 hp induction motor is 50% efficient, but it might be 75% efficient at half the volts, and a fourth of the nameplate "hp"

a 1 hp motor might be 67-75% efficiency and this allows for about 50% nameplate generation capacity.

once you get to the 2-3 hp range, then you can run the induction motor as a generator, and theoretically extract nameplate electrical hp out of it.. but the efficiency will still be significantly lower than what the motor says on the nameplate because you have to supply 3-4 hp into the motor shaft, which means your efficiency would drop to what it would be if you were running the motor as a motor at 1.25-1.3 times its nameplate "hp"


once you get to the 10-100 hp range where the motor is 94 to 98% efficient that you can use it as a generator and get 90% of its nameplate hp out of the "generator" at similar efficiencies as what's on the nameplate.


all this can be avoided by replacing the rotor with magnets.

bigrockcandymountain

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #11 on: December 23, 2017, 05:22:54 AM »
I read prairie turbines website over a couple times.  I know they built and sold a contoller.  It was a constant rpm setup and used the grid to power one coil and got power out of the other two.  I'm not sure if the controller just switched the grid connection or varied the voltage. They did have approval to be grid connected in some places.  There is one video for sure on youtube.  Might be able to contact the builder that way. 


I think the idea was that the turbine needed the grid for excitation so if the grid went down it wouldn't back feed power.  They used 7.5hp induction motor with 5:1 reduction and a 20' prop.  That is about all i can remember. 


Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #12 on: December 23, 2017, 05:50:10 AM »
So it sounds like a vicious circle. Bigger motor and bigger blades. My goal is a turbine small enough to attach to a structure and plug into the wall. But still make enough watts to justify having it. I thought 700 Watts was the sweet spot.

Yes, I watched the video and Tom Sullivan had a number of posts on the Breezy on this forum. Everything appeared to work. Most problems were from too little wind. The question I have is “what happened?”. All the posts on grid tied induction turbines ended about 10 years ago. I contacted someone on a different forum who said his was working fine but authorities raised his taxes to equal the savings he was getting, so he sold it.

As per the inverter and installing magnets. All that-I considered. However, the potential of having a final product that one could mount to your house and just plug into the wall is just too appealing. I found one on a search - Clarian Technologies “jellyfish” that did just that. However, either never made it to market or was pulled.

As to the power companies. I spoke to both in my area. Both are small cooperatives and easy to work with. They have no problem as long as I can demonstrate anti-islanding capabilities.

george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #13 on: December 23, 2017, 07:12:06 AM »
My goal is a turbine small enough to attach to a structure and plug into the wall. But still make enough watts to justify having it.

And there is the utopian Rub.
If it were that easy.....

You actually COULD plug in a 3 phase motor direct without any controller and it will push back power IF the thing is turning fast enough when connected.  Big blades and a strong constant wind would get you there but I imagine the places where this were practical would be far between.

You can do this as I have when it is engine driven which is much easier.
Thinking about it yu could use a 3phase motor and go straight to single phase. Just tap off any 2 legs and ignore the 3rd one, you would get about 2/3rds  of 1/3rd ( 3 phase) the motors power rating.
On a 10 KW motor, (direct coupled)  that would be about 2 kw

I looked at a small turbine with the same basic idea. Nothing too big but put some worthwhile if not huge watts back into the system.
I couldn't find a way of not so much doing  it but it being financially worth while.

I get some significant wind here and all I saw was energy blowing past. I thought a little turbine  attached to the shed roof would be great.  To make or buy something that will justify it's cost or come close in generated power was something I couldn't find.  Takes a fairly significant windmill to make 1 KW.  I can throw 5 used 250W panels on my roof, flat on my roof, and make that for a cost of $200 plus maybe $75 for a small used inverter.  No way i'm going to get a 1kw mill for that even if I built it myself.

I understand solar isn't for everyone and may not be what you want but just making the comparison in ease of set-up and cost effectiveness.

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #14 on: December 24, 2017, 06:47:01 AM »
I do not dispute the value of solar. Wow, $275 for a 1250 watt system with inverter. I have not been lucky enough to find a deal like that.

I am still set on working out a solution fot this project. Can you tell me what using a single phase 110 volt motor does to the efficiency? I was wondering if a 750 watt motor’s efficiency was impacted at all by the operating voltage. If not, could I use a 1.5 kw (110 volt) motor to get 700 watt production? Obviously I would need longer/larger blades. If the current ones are 5’, would the new ones need to be 10’ or is that ratio different?

jenkinswt

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #15 on: December 24, 2017, 04:43:30 PM »
I love my wind generator but it hasn't come close to my solar panels production. Its a 3000 watt Jacobs 54' in the air with no trees around but it seems to take a fair amount of wind to start pumping the kinda power out that my panels do. I currently have a 2.5kw array and even on most cloudy days its my main producer. My main reason for the mill is night time power or real dreary days. Were off the grid though so I doubt it would have been as worthwhile to cut back on a power bill. Another nice thing about solar is there are no moving parts to stress out about if your away from home.

I'm not saying its not worthwhile because maybe you could use this one to figure it out and go from there. I'm still planning a larger mill higher in the air to get some lower wind power.

joestue

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #16 on: December 24, 2017, 05:33:30 PM »
I do not dispute the value of solar. Wow, $275 for a 1250 watt system with inverter. I have not been lucky enough to find a deal like that.

I am still set on working out a solution fot this project. Can you tell me what using a single phase 110 volt motor does to the efficiency? I was wondering if a 750 watt motor’s efficiency was impacted at all by the operating voltage. If not, could I use a 1.5 kw (110 volt) motor to get 700 watt production? Obviously I would need longer/larger blades. If the current ones are 5’, would the new ones need to be 10’ or is that ratio different?


To get 700 electrical watts out of the motor, you need a 1.5 hp motor, and you will need at least 1 kw of power into the motor shaft. the voltage (120vac 60hz) will need to be reduced somewhat. i'm not sure what the optimal voltage is but it might be as low as 90vac, it depends on the motor's efficiency. i have a 1 hp induction motor, 1750 rpm, rated 1.25 service factor.. its nameplate says 73% power factor and 67% efficiency, which is relatively horrible.

anyhow to get any power out of the wind below the rpm dictated by the gearbox and the 60hz line frequency will require a vfd.
« Last Edit: December 24, 2017, 05:40:25 PM by joestue »

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #17 on: December 26, 2017, 07:22:52 AM »

I believe the wiring setup you are looking for is called C2C.
It's a pretty common way to convert 3 phase to single.

One leg from the motor goes straight through. The 2nd leg has one  cap and the third leg has 2 caps of the same value or 1 cap of Double the value. you can wire them 1-2, 2-3 and leave 3-1 open or direct connected. Use 440V caps or the highest you can get.
You can tap off any 2 legs you want back to AC.


Thank you, Yes it worked. But a small victory as I have learned this motor will not give me the power I was hoping for. My cousin, who made this, wants to try a different motor and blade combo. In the meantime, I am going to look more at controls. I was hoping to hear back from Jondecker76 and have one ready made, but no luck on that.

george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #18 on: December 26, 2017, 12:54:09 PM »

How much power you wanting to get?

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #19 on: December 26, 2017, 01:07:27 PM »
I was hoping to get between 600 - 700 watts

SparWeb

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #20 on: December 26, 2017, 01:55:01 PM »
Peak power, or averaged over the whole year?
Two completely different turbines needed, depending on your answer.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #21 on: December 26, 2017, 02:09:42 PM »
I would like to get 1642 kw per year based on ave wind speed of 12 mph.

kitestrings

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #22 on: December 26, 2017, 04:50:50 PM »
Hi Kyle,

I don't mean to discourage your creativity, but please be careful with this project.  I've dabbled in wind for years, and I also now work for a Coop here in VT.  I certainly can't speak for all utilities, but the folks I work with pretty much just don't want anyone to get hurt, or put their property at risk when it comes to interconnecting a DIY system (wind, solar,...home-owner wired house/camp/stand-by genset, what-have-you).

Quote
I hope to spin it up and when it is close to sync speed, (ala hall sensor) cycle off the power and let the wind bring the rpm above sync before powering back on to generate.

This to me is down-right scary, both because if the two are not "in synch" (likely where this expression originates) it will put ungodly stresses on things, but also when it is unloaded it will speed up very, very fast in high wind.  You may not be able to control it when you want to...

Okay, that out of the way, what you are considering IMO seems unnecessarily complicated.  Years ago I worked for a small wind manufacturer that made induction turbines (and sold other types, models).  If you're on a single-phase service why not just use a single-phase motor.  There were a number of designs like the Enertech's that I'm most familiar with, where you simply motor the thing up when there is ample wind - usually determined by an anemometer - running in synch, at its intended frequency and voltage, and then when there enough wind the motor/generator goes above its synchronous speed, and the current reverses direction.  Much simpler.

You probably need gearing, or some type of speed reduction to the prop.  You still need anti-islanding protection, but now it is comparable to connecting a stand-by generator, or other rotating generator (methane digesters and the like).  You still need one other thing, and this is important, a means of safely shutting the thing down when any given component fails (relay/transfer, 'hall sensor', gearbox).  Enertech first used mechanical, then hydraulic braking....but eventually went to dynamic braking (electro-mechanical braking, like on you chop-saw), and tip-brakes.

Happy Holidays.  I wish you luck, but please be careful.  This is no small challenge.

~ks

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #23 on: December 26, 2017, 05:05:44 PM »
Ks,
Thanks for your input. I was under the impression that the induction motor had to be "off" until it was above 1800 rpm. Which is why I was trying to "pulse it in". If it is just as easy as turning it on and waiting for the wind to take it there, I am thrilled.

Single phase motor: Yes, my cousin, who is doing the fabrication, has already got a single phase motor and new blades coming to me. I have an anemometer with one relay, which will engage the turbine when wind is above threshold and disengage at low wind speed.  I also have a hall sensor to measure motor rpm. I am still working on how to sense grid loss and would welcome any suggestions. As I said in an earlier post, jondecker76 posted the exact set up I want, but have not had any luck contacting him.

Braking: I am looking at dynamic braking for stopping it in high wind or grid loss and have another relay I think will accomplish that.

george65

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #24 on: December 26, 2017, 06:01:10 PM »
I was hoping to get between 600 - 700 watts

As I said in my first post, you aren't going to get near that with a 750W motor.

As for single phase, you know you have to take out the start capacitor and modify the switch ? Not a matter of throwing blades on the thing and hooking it up.  The problem with doing that in any case is unless you have good winds, the thing will be a fan USING power till the wind gets up to speed. Depending on the blades and the load they impose when it is motoring, you could overload the thing very easily as well.

I don't know how big single phase motors go to in the US but here it's about 3HP but in any case, you would be wise to get the biggest single phase motor you can.

This is never going to be without a controller or straight plug and play so I would suggest looking at another type of generator conversion like an F&P motor with something like a small grid Tie inverter.  This would give you everything you need with syncing, anti islanding etc.
You could either go direct with the F&P through a rectifier or use a voltage Doubler to get the voltage where it needed to be for the inverter input.  Just depends on the input the inverter needs and the prevailing  wind speed and blades you put on the motor.   F&P's with a grid tie  are a very successful combo and produce the sort of power you want.

Other than that, Might be better to look at an alternator converted to PMG with magnets. These can be bought on the net and there is a controller for them as well.  Not exactly cheap IMHO but you can always DIY them if you prefer. Again with these permanent magnet types that don't need energising to work, all you would have to do is run them through a cheap Inverter like a power jack or the like. That is going to save a LOT of hassle if you aren't knowledgeable enough to make your own controller.

It seems you have got caught up on an ideal that doesen't really exist so I guess it depends if you want to pursue that to make it work with all the complication you were initially trying to avoid or change paths for something much more simple and effective.

JW

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #25 on: December 26, 2017, 06:25:10 PM »
jondecker76 is one of the few "really oldtimers" that does not have a email in the profile or the system.

your best bet is going to the upper right to the page hyperlink "OTHERPOWER" I don't want to get leads to spam But try to get a hold of Dan Fink. There's a email for him.

JW

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #26 on: December 26, 2017, 06:45:35 PM »
I found this using the "Google search" [ THIS SITE] at the bottom of the home page and entered 

jondecker76

http://www.fieldlines.com/index.php?topic=138266.10;wap2

""""The other thing I notice different is that these larger units use a slightly different control board, has an SCR bank, and uses an EnerPro SCR firing board (which is actually a modified AC motor control board - as I spend quite some time on the phone with Enerpro engineers pouring over schematics to re-enable the soft start feature of the original AC motor controller)
We are putting this unit on another 40KW Enertech this week near Erie PA, then on 2 60KW Enertech machines the week after, also near Erie, PA""""

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jondecker76:
 From your description, the control system sounds spot on to how these larger units operated (Except for different values for windspeed). The control system has its merits (mainly that because it is spooled up from the grid, it will be perfectly in phase as it crosses the alternators synchronous speed, and therefore have very minimal THD on the line). However, in practice for us, it has been horribly inefficient - and since it does not monitor alternator RPM, it has to err on the safe side and kick offline way earlier than it needs to - based purely on assumptions gleamed from the windspeed.
The other thing I notice different is that these larger units use a slightly different control board, has an SCR bank, and uses an EnerPro SCR firing board (which is actually a modified AC motor control board - as I spend quite some time on the phone with Enerpro engineers pouring over schematics to re-enable the soft start feature of the original AC motor controller)
We are putting this unit on another 40KW Enertech this week near Erie PA, then on 2 60KW Enertech machines the week after, also near Erie, PA.

StorminN:
 Hi Jon,
I just consulted the Enertech manual...
"The control system is factory pre-set to operate in response to the following 30-second average windspeed data when run in the AUTOMATIC mode.
Over 11 mph - Start-up

Under 8 mph - Shut-down

Over 40 mph - Shut-down ("cut-out")

Under 30 mph - Start-up ("reset")
The control system can also be run in a TEST mode, which has the effect of by-passing the start-up and shut-down controls, and permits the owner to run the windplant even when winds are below start-up speed."
I also looked it up... the gearbox is 11.4:1

There's an electrically-released, triple-disc spring-loaded brake located between the gearbox and the generator. On the far end of the generator (the nose), there's a small box with an emergency overspeed switch inside. It's a centrifugal switch, if the generator overspeeds, this switch interrupts the electrical circuit to the brake and stops (hopefully) the turbine.
So I don't think there's any electronic braking that happens with this smaller control box, just the mechanical disc braking?... but it would be very cool to see how much more efficient a freewheeling turbine is as opposed to one that's braked too often and then powered back up. Do you have any figures as far as efficiency gain? With two identical turbines close to each other like you have in your picture, you might have gotten some numbers?
Thanks,

-N.

jondecker76:
 I wish I had the foresight to do such a comparison, but the thought didn't even cross my mind. Early indications are that it is much more efficient (my guess at this moment would be around 25%) and the owner of the twin 40KW machines seems to agree after having these online for about a month now.
I will see if I can talk the owner of the twin 60KWs into letting me do this type of test for a month or so (his towers are almost up now, so they should be flying this month)
11.4:1 gearbox... Yours will be much quieter than these with the 30:1 gearing... The 40KW and above units are quite loud!
I would also be interested in hearing how the local power company deals with you in getting this set up..  We had problems with everything from distortion, failsafes and power factor (where they finally agreed to provide the capacitor banks for us)
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« Last Edit: December 26, 2017, 07:11:06 PM by JW »

joestue

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #27 on: December 26, 2017, 06:54:31 PM »
the concern about simply hot plugging the motor when its above synchronous is a valid concern, but the most torque you're going to get out of the motor is about 2-3 times the nameplate "rated hp"

and yes you can just plug in a single phase motor and push shaft hp into the motor. you don't even need to take out the starting switch and capacitor, because above whatever rpm 40hz is they will disengage.

replacing the start capacitor (most >1 hp motor have a run capacitor as well) with a run capacitor if it doesn't have one will increase the efficiency.


anyhow the efficiency of <3hp induction motors is relatively horrible. you would be better off with a motor conversion and spending 1$ a watt for a grid tie inverter. (depending of course, how much the tower and your time and the blades are worth to you) if the tower, gear box and blades are relatively free, then making them larger and using an inefficient motor will get you more kilowatt hours per dollar.

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #28 on: December 26, 2017, 08:22:54 PM »
jondecker76 is one of the few "really oldtimers" that does not have a email in the profile or the system.

your best bet is going to the upper right to the page hyperlink "OTHERPOWER" I don't want to get leads to spam But try to get a hold of Dan Fink. There's a email for him.

In doing a reverse search for him, he did offer his email in one of the posts. I sent a message to that and have not had a response as of yet. I also messaged both of the Prairie Turbine developers with like results. I am holding out hope that after the holidays, I get a reply.

Kyle

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Re: Help needed on a Breezy type grid tied induction turbine
« Reply #29 on: December 26, 2017, 08:34:33 PM »

anyhow the efficiency of <3hp induction motors is relatively horrible. you would be better off with a motor conversion and spending 1$ a watt for a grid tie inverter. (depending of course, how much the tower and your time and the blades are worth to you) if the tower, gear box and blades are relatively free, then making them larger and using an inefficient motor will get you more kilowatt hours per dollar.

Yes, for the most part, they are free for me to tinker with. The goal still is to keep the turbine small enough to manage without equipment, mount on a building and still put out enough juice to supplement the electric bill. Knowing now how inefficient the smaller motors are really disappoints me - but I still want to try and see what I can get.

How do I detect grid loss? Is there a specific sensor or device?