Prairie Breezy Turbines again?

[clintonbriley]

1 PPR (or even 100 PPR) is just too low resolution

Hey Jon,
It's good to see you posting on this subject again.  I followed your original posts when you were programming your
first plc controller for induction turbines.  I was impressed that you were able to turn your project into a
business.  Anyone here who is interested in the electronic control aspect of induction wind turbines would
likely agree with me that you have a lot of valuable experience of offer.  I read your post and would have to
agree that 1 pulse per revolution would be a poor way to measure rpm if the hall effect sensor counted pulses.
It would be impossible to accurately control an induction generator turbine if this were the case, but it's not.
Your assessment that at 1800 rpm there would be 30 pulses per second is correct, but a single pulse is all that
is necessary to determine rpm.  Instead of counting revolutions, the hall effect sensor, simply put, measures
the velocity of the magnet.  So at 1800 rpm the breezy's hall effect sensor (with one magnet) is telling you the
rpm 30 times each second.   Add another magnet 180 degrees from the breezy's single magnet and you will
get an rpm reading 60 times per second instead of 30.  I don't know if it is better or worse for the wind turbine
application than the optical encoder you have been using, perhaps you can reevaluate the device objectively and
share your findings here.

This is why you either have:
A) An induction turbine that is inefficient in lower winds
B) An overly-expensive and overly-complicated hub design with pitch control. This gets around the problem of
being inefficient in lower winds, but puts it out of the realm of most hobbiests.
C) I haven't seen it personally, but a passive yawing system could work here - but keep in mind that even smaller
induction turbines easily weigh into the thousands of pounds - so engineering such a system could be a bit difficult as well

A) would define the breezy.
B) is my pet project.  I'm attempting to design a (passive torque sensing torque regulating hub for use with an induction
motor/generator) that is minimally complicated that could be built at minimum expense.  This would be torque regulating
only at first, to verify that it works, and if it does, centrifugal overspeed pitch feathering would be added.  Yeah, it's a tall
order, but maybe not impossible.
C) one of the Jacobs induction generator type wind turbines does this.  It has a 90 degree gearbox that steps up rpm and
turns a verticle shaft that powers a generator below the nacelle.  This means the turbine is constantly trying to turn it self out of
the wind as the turbine turns, but the tail resists this action.  The tail being spring loaded, allows the turbine to turn out of the
wind only when the torque becomes high enough to overcome the force of the springs.  This turbine also has the classic centrifugal
pitch control hub as a safety feature in case of brake, gearbox, etc., failure.

They do have a place in alternative energy, but low wind speed areas and the hobby market haven't had a whole lot of experimentation
and there is a pretty big lack of information in this area.

I agree.  And I know that in my wind zone, it might never pay for itself even if I build a reasonably good one on the cheap, but I'd still love
to have one. :-)

All that aside, apparently the breezy now incorporates a "soft start" device in their controls.
Can you shed some light on how this works?  I read in one of your posts that some of the turbines you made controls for also have
a soft start feature.

Clint

[jondecker76]

RE: hall effect timing -
Yes, I am aware that they are counting deltatime between pulses. The problem is, that at there would only be a difference of about 20us (millionths of a second) in the delta time between 1800 RPM and 1801 RPM. Some of the best microcontroller, even while using interrupts, are only capable of 4us accuracy (mostly overhead for processing the interrupt, etc).. That alone produces a 20% margin of error - and thats if your microcontroller can even pull off a 4us accuracy (most are more around 8us... But even with a microcontroller capable of 4us resolution, your reading will only be accurate to about 5 RPM) I did extensive research of delta timing to determine RPM when I built the PLC controller, and its simply inferior to calculating by the number of pulses over a set period of time. I do believe this is a major drawback to the Breezy design and greatly adds to the poor performance in lower wind zones.

RE: Soft Starting
I currently do this with an external soft-start card which gently brings in the SCRs via PWM. Breezy uses off-the-shelf soft starting scrs/zero-cross relays. In my current development using a microcontroller, I will be leveraging the fact that I can monitor output as well as create my own PWM signal. This will allow me to start as soft as possible while remaining in the RPM gap of the slip rating. Basically, by staring with a low duty cycle, you can slowly coax the turbine into phase with the grid (as it is possible to be as far as 180 degrees out of phase).  This will decrease the harmonic distortion created when you first cut to the line... But, do it too slow, and the turbine will slip-out... Do it too fast, and you create a pretty good harmonic spike that the utility will definitely thow fits about. In my current PLC controller, we had to be a bit overly-aggressive with the soft start card, as it has to work even in the worse case scenario (its ramp up from 0 duty cycle to 100% duty cycle is fixed) - most soft-start SCRs are the same.  By using my own microcontroller, I will be able to be as soft as possible in all cases (a big reason that I started development of my own board - I started to be held back by the limitations of the PLC I am using).  I've also seen designs that only use a contactor, and slam the turbine directly to the grid. They still work quite well, but you can actually hear the thing "groan" as it fights to get in phase.. But these types are grandfathered in, and you'd have little luck getting the graces from your local utility to connect a "hard starting" system like this.


Most induction wind turbines fight phase angle differences in a different manner all together.. They will monitor windspeed until it is determined that there is enough wind for the turbine to generate useful power. They will then use the grid to motor the turbine up to speed, so that it is in phase with the grid as it crosses over synchronous speed - in which case soft starting and phase angle issues disappear. The problem is, this greatly adds to the inefficiency in lower wind zones, as you may be sucking energy from the grid several times per hour to start back up as the windspeed cycles in and out over the predefined limit (These 40KW and 60KW Enertechs originally operated in this mode). This also used to cause these units to eat its brakes every 4-6 months, at a cost of about $400 to replace. This is the main reason I designed the "free-wheeling" controller, as it makes these turbines much more efficient in lower wind zones than they were designed for

[clintonbriley]

Ahhh, Thanks for making it more clear Jon (and repeating yourself some) sorry I wasn't listening closely enough the first time.
That's a good explanation for the soft start feature.  So the early breezy turbines did a hard start and certainly
put some harmonic distortion onto the grid.  Do you suppose the power companies allow more leeway for the
smaller output turbines?  Also, the breezy 5.5 used a torque slip clutch set slightly above the high limit cutoff point. 
Do you think this woud be any advantage to getting the generator in synch with the grid more quickly?  Other
reasons are listed for this, but the synching issue isn't one of them.

You had mentioned in the past that you wanted to build a smaller scale induction wind turbine, have you built
one yet?  What type of wind zone do you live in?
Clint

[KeithOlivier]

Folks, new face here, but here is my 2c on this issue:

It seems like the fundamental problem with the Breezy concept is that there is no variable element to compensate for variation in wind speed.  The large turbines vary the blade pitch.   DC turbines drop their voltage as wind speed drops.

It sounds to me as if the breezy needs 2 separate inverters.  The first, directly coupled to the turbine which has a variable mains frequency to track wind speed.  As others have said, an anemometer or something similar positioned appropriately and sufficiently damped to provide a wind speed input, which then determines the primary inverter frequency.  The lower the wind energy, the lower the mains frequency to which the blades have to "synch".  There has to be a lower cut off and some hysteresis so that one isn't cutting in and out in marginal conditions.

The variable frequency AC produced is rectified to DC and then converted back into fixed frequency AC by the grid tie inverter.

Going this route will permit operation of the mill at substantially lower power than what is afforded by the current controller with very little in the way of changes to the basic machine.  If the wind speed vs operating frequency is handled by a mathematical formula or an interpolated look up table, it also provides a flexible "tuning" element in the system to take into account and compensate for factors like blade design, motor/transmission line "stiffness" etc.

Best regards
Keith Olivier

[clintonbriley]

Hey Keith,
Three phase motors can be set up to provide variable speed output by using a variable frequency drive device.
I have read that there are some induction turbines which basically use variable frequency drive units in reverse.
From what I understand, these units work much like the idea you describe.

Inverters are still fairly expensive and one of the advantages of using an asynchronous generator in a wind turbine
is that an inverter is not needed.  Another advantage is that the generators/motors are stock items that can
be purchased "off the shelf" fairly cheaply.

[KeithOlivier]

Clinton:

In this day and age, I would be very surprised if there is any utility company out there which will allow the connection of a turbine to the grid without an inverter.  In the 3-4kW range, the Sunny Boy grid tie inverters are in the $1600-$2000 range http://sunelec.com/index.php?main_page=index&cPath=6_37  I know the Breezy is touted as a 5.5kW source, but perhaps one needs a special location to realize that.

The thing is, once you have the grid tie inverter anyway, there is no need to feed it fixed frequency AC.  It seems that for several owners, doing this defeated the entire point of spending all the money and doing all the work, since the power level was seldom realizable.  I have been looking for regenerative type variable frequency drives, since these will commonly allow the use of an analog voltage to drive the operating frequency, but these are still rare beasts at the lower power side of things.  I too like the concept of using a conventional induction motor, but I would simplify it a bit and do away with the gearbox and the proprietary drive system.  I have been reading the FAQ on converting induction motors to PMG's and that is a fascinating read, since one does not have to have an enormous amount of cash locked up in one of those and can do away with the gearbox too and drive direct.

[clintonbriley]

In this day and age, I would be very surprised if there is any utility company out there which will allow the connection of a turbine to the grid without an inverter.

They connect them to the grid all the time.  Almost all of the utility wind turbines use ansynchronous induction generators without inverters.  I've read that there are some (big ones) that are direct drive permanent magnets designs (which may use inverter technology), but they aren't quite cost effective enough and/or well proven enough to take over the market (at least not yet anyways).

 

I know the Breezy is touted as a 5.5kW source, but perhaps one needs a special location to realize that.

To realize 5.5 kw with the breezy, all you need is a 23 mph wind, not a special location.

The thing is, once you have the grid tie inverter anyway, there is no need to feed it fixed frequency AC.

I don't have a grid tie inverter, and there would be no point in using a grid tie inverter with an asynchronous generator.
What is the expected lifetime for a grid tie inverter?  Lightning can certainly fry one.  Are they easily repairable at low cost
after a lightning strike? I don't know the answer to these questions.  Do you know off hand?

I too like the concept of using a conventional induction motor, but I would simplify it a bit and do away with the gearbox and the proprietary drive system.

By simplifying the induction motor (making a new rotor or modifying the old one, fitting it with permanent magnets, and running it direct drive) you end up
with quite a low output generator (in terms of what its original output potential was) and all of the original weight too.  It's a facinating read I agree.
What is the proprietary drive system you mention?

If you are going to make a permanent magnet generator, there have been compelling arguments on this board, that the axial flux design is the way go
cost wise.
Clint

[KeithOlivier]

At this link you will see that an inverter is required in every installation and the inverter has to comply with UL standard 1741.  Look up "Net Metering" in your state and see what the rules are.   The format above seems to be widely adopted everywhere I have looked (places I may choose to live).

http://www.michigan.gov/documents/mpsc/net_metering_handout_2010_Energy_Fair_330553_7.pdf

You can read here http://ulstandardsinfonet.ul.com/scopes/1741.html about the scope of UL 1741.  If you propose using something other than an inverter, you would have to prove to UL that your method would be in compliance, which would probably be quite an expensive process, certainly more expensive that a 7kW inverter.

[ghurd]

By simplifying the induction motor (making a new rotor or modifying the old one, fitting it with permanent magnets, and running it direct drive) you end up
with quite a low output generator (in terms of what its original output potential was)

Maybe I misunderstand the "original output potential", but I think I disagree?
Jerry documented well over 1KW of actual output from 1HP garbogens (garbage disposal and obsolete HD magnets), and over 1KW with 1HP ECMs.

Others have got ~175W from 1/3rdHP ECMs with minor modifications to be suitable for lower winds, and they could get a lot more output if modified for higher winds (guessing near 300W).  I am pretty sure they could break 500W if set up basically to only work in high winds.
With nothing more than a Snip & Solder operation.
G-

[clintonbriley]

Maybe I misunderstand the "original output potential", but I think I disagree?

Hey Ghurd, my mistake was considering only large hp conversions.  The smaller hp would be more compatible with
a direct drive blade.  When you go bigger and direct drive the rpm input gets smaller and smaller the larger the
blade set.  It would be necessary to use a gearbox or belts, etc (and a large blade set) to get good power from the larger hp conversions.
Clint

[clintonbriley]

At this link you will see that an inverter is required in every installation and the inverter has to comply with UL standard 1741.

Here is a quote from the link you provided....

Net metering is available to any customer meeting the generator size requirements (20 kW and under) and using a UL 1741 certified inverter.

here is a quote from the breezy site....

It seems like the larger the power company the more positive the response. Some of the smaller companies do not have a clue as to what asynchronous generation is or how it works. One company required that the generator complied with a UL code that was for an inverter, saying that if it didn't have that particular code stamped on the controller it wouldn't be accepted for connection to their circuits. They must have took the matter up to higher management and at some point later stated that have to test the generator to make sure that it was an asynchronous generator and that it wouldn't degrade the quality of the power in their circuits.

also mentioned on the link you provided is this catagory....

Modified Net Metering – Methane Digesters: >150 kW up to 550 kW

methane digester systems use asynchronous induction generators, so they are saying on this link that asynchronous generators are acceptable.
They don't use inverters and there is no mention of them needing to be UL listed. I'm sure the power company would need to sign off on the installation though.
Apparently, since almost all small turbines generate DC current, power companies are not as accustomed to a homeowner installing
wind turbines that use an asynchronous induction generator for grid tie.

[KeithOlivier]

It looks like Tom, one of the original contributors to this thread, decided that by running the system as designed it was a complete waste of time since the "available power" at his site was typically at or below "cut in power".

I don't know how much he had invested in his breezy + 140ft tower, but I assume it is a considerable sum and making the system work for him for another $3k would have probably been acceptable and less investment than any of his other options.

Those who started this thread have identified a valid operational flaw in this turbine, which at this point can't be cured by "simplistic" means, however desirable that may be.  Of the options (mechanical or electrical), the electronic option has the least impact and will certainly have the least maintenance overhead. The utility turbines have the mechanical option (far from simplistic).  All utility customers who have a DC generator or PV installation are using inverters and I have not heard of entire counties being wiped out by the passage of a single electrical storm.  Risk is everywhere and must be mitigated but cannot be eliminated.  A direct lightning strike to a utility pole near your installation will probably fry something, inverter or not.

[clintonbriley]

It looks like Tom, one of the original contributors to this thread, decided that by running the system as designed it was a complete waste of time since the "available power" at his site was typically at or below "cut in power".

Yes is does look this way.

I assume it is a considerable sum and making the system work for him for another $3k would have probably been acceptable and less investment than any of his other options.

I would be interested to know what additional cost Tom would consider to be acceptable for a minimum improvement in generating capacity.  Maybe
he will share that with us.

Those who started this thread have identified a valid operational flaw in this turbine, which at this point can't be cured by "simplistic" means, however desirable that may be.

Several people have identified multiple flaws, I'm not disputing that, I agree, but that's part of what makes it such an interesting subject.
All of it's flaws might be lessened or eliminated with the application of the right ideas, ideas that might come to light from the interaction of
people on this forum.  When you say "simplistic means", what is your comparison?  Even though there are step by step instructions for building
several variations of axial flux permanent magnet alternator wind turbines, most people would not describe the idea of building one as being a simplistic task.

It is possible to build a passive pitch control hub which will fix or improve 3 of the breezys issues.
Those issues being:
1:  Poor performance in low winds.
2:  Constant cycling on and off if wind isn't quite strong enough to keep it engaged to the grid.
3:  It doesn't have redundant turbine overspeed protection due to (among others) brake failure.

I say it is possible because there are examples out there of these types of control.  Designing and building one may not be simplistic, but as I see it,
neither are the other alternatives.  If the hub existed and it were installed, then one could measure the performance and compare all of the
variables to a permanent magnet system.  Until that time I prefer to keep an open mind.

A direct lightning strike to a utility pole near your installation will probably fry something, inverter or not.

Agreed, but there may be significant differences in the cost of damage to different appliances and some may be
much more sensitive to a lightning strike than others.  Induction motors are resistant to lightning damage.  A computer based controller
would be sensitive to one though.  I wrote previously that I don't know how susceptible the inverters are to lightning damage, or how much a
typical repair might run.  Maybe the majority of the components are close to bullet proof........  I'd be great to hear from someone who has
experience with them.

[Tom Sullivan]

   I had about $14,000 in the whole system.  I figure the turbine was about $4,000, the tower about $8,000 and wiring and controls about $2,000.  I got back $4,000 on my taxes, so my net in the wind turbine now is $10,000.  Of course, we need to deduct the $60 in electricity I generated over 18 months as well (sorry, couldn't resist).

   I wouldn't consider any serious amount of investment to the Breezy at this point.  Too many issues and I'm not confident it will ever be productive in my wind zone, regardless of any improvements.  My attitude could change with time, but you have to realize the frustration from the incredible amount of work and money invested compared to the return.

   On the question of getting this unit grid tied; no problem.  My local utility scheduled an appointment and had a pretty sharp technician come out and put it through a bunch of tests.  Much of what they needed was relayed to me by another Breezy builder that had his inspected and approved several months before mine.  They had some definite standards, some different than other states, but in the end, they were pretty reasonable.

Tom

[clintonbriley]

Hey Tom, thanks for sharing the cost of materials for your breezy setup, looks like you did a good job of keeping costs
down considering you more than doubled the tower height from the breezy plan book.
Was there any charge for the power company to connect your turbine to the grid? 
Did they provide an additional meter? 
Is there a monthly charge for the extra meter?
And it probably wouldn't have made a difference with the low production you saw with your turbine,
but does your power company allow you to "bank" extra production monthly like some do?
"Net metering" can have many different definitions.
 
Clint

[Tom Sullivan]

Clint,

My local utility charged me $100 for the grid tie application.  They provided a separate meter for tracking any excess generation.  You "bank" the excess for up to a year (if you were able to produce that much) and then they would pay me double the current customer rate if there was a positive balance after a year.  My utility provider is WE Energy.  They were great to work with.


Tom

[tdmack]

I would like to address a few of the issues mentioned and offer some of the results of our efforts to make the turbine more efficient in low wind and turbulent areas.

Turbines experiencing low production numbers can usually be placed in two groups:
Turbines operating in a low wind zone (must be very high zone 2 or a zone 3 min.).
Turbines placed in good wind but operating in turbulence. These turbines can be identified by  their cycling on and off line with wind speeds in excess of 12 mph and wide yaw angle as the turbine seeks to equalize pressure across the rotor.  We have found that turbulence will absolutely rob large rotors of their power.

We've tested a few methods to increase power in low and turbulent winds:
Increased blade length
The standard blade  (similar to 4415) for the 5.5K is 9'long (10K is 11.5').
Tests done with 5.5K turbine for several months:   Increased blade length to 10'
Increasing the blade length to 10' in a very turbulent location provided a dramatic increase in power production.  Power output in winds over 27 mph routinely exceeded 7KW.  On two occasions sustained winds in excess of 40 mph for periods of 18 hours resulted in burned motor stators.  Medium to high winds from a direction greatest turbulence caused occasional overspeed shutdown as the generator field was unable to lock onto the rotor. 
 
Conclusion: This method will improve average power output in turbulent air.   Wind speed override controls must be in place to limit upper wind speed operation.  Turbine rotor hub must be reinforced to operate with additional forces applied by the larger swept area.


Stator switching for low wind operation.
This is a little different method of stator switching I came up with a couple years ago.  Using this method will effectively divide your motor in two.  So if you are using a 7.5 hp motor you now have a 3.75 hp motor (with a turbine rotor that's way to big). Three things are required for this: a Y wound dual voltage 3 phase motor (most of the builders are using this motor) and a 3 phase relay with a failsafe circuit.  Adjustable current monitoring relay.   By disconnecting the “4-5-6” motor straps in the motor connection box one half of the motor has effectively been disconnected.  By reconnecting them by way of a 3 phase relay with one side strapped together you now have a 7.5 hp motor.
Conclusion:  Once the turbine comes online it stays online much longer. Short cycling is reduced from as much as 6 times per minute to 1 or 2 times per minute (this is at the very lowest region of operation).   Current monitoring relay is necessary to control relay switching. Circuits should be incorporated to add failsafe when using this method. On the downside this method adds risk that a failure of the relay or control circuit could prevent the second half of the motor from reconnecting resulting in a burned stator in winds from 15 to 17 mph. Higher winds should put the turbine in overspeed shutdown.

Servo controlled tail: 
This test consisted of  furling the tail via hydraulic servo with input derived from generator current.  Theory was (emphasis on was) that we could use a very large turbine rotor and just furl it out of the wind enough to keep the motor current a maximum.  Continuously monitor current and the servo would make adjustments as needed.

Conclusions: This method would require a huge tail vane.  The tail is virtually ineffective when the turbine is running.  With the tail 90deg to the turbine and reaching 3' beyond the turbine rotor diameter it had very little influence on the rotor.


Other notes: on topics previous in this thread
The rotors are of passive stall design.  They operate in four phases.
Drag: rotor is coming up to speed
Lift: rotor is producing power
Stall: rotor begins stall near hub and progresses towards the tip
Drag: rotor is held at full torque with very slight increase
A benefit of using straight blades is that the stall happens progressively.

The micro-controller does use the time between magnet sweeps across the hall-device  to determine rotor speed.  It can be programmed to control speed to .25rpm increments (that is 1801.25, 1801.50..etc.) 

Tim

[clintonbriley]

Hey Tim,
   Thanks for posting some of the various attempts you have made to improve the turbine in lower winds,
it's good to hear what your findings were.

Is the stator switching method you describe the same as what's called split phase?
What is the difference in minimum wind speed that will keep the turbine locked to the grid continuously
between the full and half stator mode?

Using tail furling on turbines has been a major subject on this forum and is still revisited from time to time.
It has been pointed out that at some point (perhaps between 20 and 30 feet in diameter), it is no longer
practical to use a standard tail because of the size that would be required and because a tail can
yaw the turbine too quickly causing excessive gyroscopic forces.  Using a geared yawing system
is typically employed for the larger turbines and can be done actively with motor drive control or
passively with a "fan-tail" such as what was used on the old dutch grain grinding windmills. 
One additional benefit with a geared yawing system is that the turbine can't yaw too quickly. 
A "fan-tail", or a "motorized" yawing system could be designed to work with a servo controller. 
This would also allow you to virtually eliminate the constant cycling on and off during barely sufficient
winds by setting it to a partially furled position when off-line and when the rpm's are high enough
for cut-in, the turbine can be un-furled allowing the turbine to operate at its full potential staying engaged
continuously.  As for using a standard tail with the servo control system, it seems to me that if the rotor
shaft were offset from the yaw bearing, it might allow that to work more effectively by using the wind force on
the rotor to help the tail turn it out of the wind.  Perhaps someone here can verify whether that would
be the case or not.

A passive or active pitch control hub would do the job as well.  I've been making some progress on paper,
in designing one that is passive and not overly complex, but have not attempted to build one yet.

Clint
 

[tdmack]

Clint

A “split phase” motor is a motor that has additional windings used for starting purposes.  These windings will usually get hot and burn out if not switched out of the circuit when the motor reaches operating rpm.  Others may have found a method of using them for other purposes though.

The method I was referring to takes advantage of the features contained in the windings of a “dual voltage” 3-phase motor (the motors most folks are using for the Breezy).  Industrial motors in the lower horse power range are manufactured with the capacity to operate on 240 or 480 volts.  These motors have 2 identical sets of windings connected in parallel or series depending on which voltage level they were being connected.  When wired for use on the turbines they are wired low voltage (windings parallel) 240 volts.  I was simply using a relay to connect and disconnect one set of windings (½ of the motor) to remove ½ the load from the turbine rotor.  This doesn't necessarily change the kick-in wind speed as it changes the length of time it takes to harvest the energy from the energy at that speed.  The result is that the turbine does not cycle as often at that speed.  Although it works this method adds complexity to the control circuits also adding risk of failure.

I believe we have seen better results by using the new soft start relays.  They are true phase angle fired relays which allow us to set the kick in speed much closer to the balanced rotor speed.  The relays are adjustable for a 1 to 10 seconds to full on and are producing excellent results with the 1 second setting.  The turbine eases online with no noticeable noise at all.  If the blades are built per plans there is no more noise from this turbine then any other turbine out there and I believe anyone who has built the turbine and followed the blade plans would agree that they are among the quietest.

The Breezy being a homebuilt ( or kit built) was not designed to compete in features with the $40,000 - $60,000 turbines out there.  It is what it is, a simple asynchronous induction turbine.  Also, it won't work well in a class 1 wind area in the middle of a forest.   At a minimum it needs a very high class 2 or greater wind zone and 60' above ground in open areas and at lease 30' (45' if possible) above obstructions within 300'.

Tim

[fabricator]

After all the threads on all the various wind forums by people trying to make the breezy into any thing but a hobby, I can't imagine anybody spending a dime on the thing.

[tdmack]

There are builders out there who have been very successful with the  turbine and have built multiple Breezy turbines.  Alvin who Tom Sullivan mentioned earlier in this thread has built and is flying his 2nd Breezy…..really!  Actually when reps from Saskatchewan showed up in the area to check on their investments in private owned turbines (government incentives) Alvin's turbines were the only ones running that day.  Alvin scratch built both turbines.   


Tim

[gsw999]

The breezy looks like a nice turbine , something for the more serious builder I think.

[tdmack]

Tom Sullivan was never able to make his turbine produce primarily because he is in a zone 1 wind class…….. Basically, not enough wind to support a grid tied wind turbine.   

Problems he described when the turbine would go into overspeed and shut down were caused by grossly oversized blades.  These huge blades were just overpowering the generator causing it to shutdown   Overspeed is a shutdown mode (safety feature) activated when the controller detects a problem.  Most all controllers have this feature these days.



Tim McCall
Prairie Turbines

[Gareth G]

Hello fellow wind enthusiasts:
   I have a 10KW homebuilt Breezy turbine. My ammeter shows 40+ amps at blade stall; according to the utility meter I am only converting these amps at 50 - 60% power factor. At every stage of interconnection the power factor is much lower than expected. I do not believe the utility meter is wrong; they have numerous solar installations. Any help someone could give would be appreciated. Are there any 10KW Breezy owners that could help me with this problem? Or anyone else for that matter? Does anyone know if a wattmeter can be hooked up to a 10KW Breezy controller? Thanks.

[dnix71]

Impedance matching. You are taking wild three phase and making 240 split phase to backfeed, correct? Does this go to batteries or is it a direct grid-tie?

[Janne]

If by power factor (power factor = active power in relation to apparent power) you really mean it, then it sounds about normal. As far as I know, Breezy has an induction motor (generator).  It is spun over the synchronous speed, hence it's feeding power back to grid.
Because of it's nature it requires reactive power for magnetizing the rotor, 50-60% power factor does not sound too unreasonable.
If your utility is billing you for this reactive power, you can also make the required reactive power with external capacitors.