My small wind generator build

[Xringer]

Well, looking at the amount of steel that's been removed from the center area,
IMHO, they made a design mistake with those holes.
I doubt the bending would have occurred if not for the weakness caused by those holes.

I wonder if they just added the holes to this product? And you are the beta-tester?

I would not order a new one, unless they omitted the big holes..
Which would make it cheaper to make..

Maybe you should post the company name and URL, so when people who are looking
at this kind of product will see what can happen with this design..

[jwxr7]

Here are some pics of the hub. I don't think it was exposed to any more than 35mph.



Along with the convexing there is a wierd ripple effect around the OD caused by each blade. It isn't exactly uniform either.

I wonder if they just added the holes to this product? And you are the beta-tester?

All the 6 blade hubs I've seen them sell, are like mine.

I emailed the company to see what they think. I bought mine off the auction site, but this seems to be the company's home page. Hydrogen Appliances Wind turbines generators sustainable energy mill airx 403's wind generater mill wind 403 403 303 55555 generator powers lakota wind power airx generation Wind turbines wind mills wind power wind power generation

Here's the blade/hub page
Wind turbine blade propellers wind generator blades carbon fiber Wind turbine propeller blade MILL Permanent Magnet Alternators PMA wind power PMG PMA Aluminum wind turbine wind turbines
My blades and hub are pictured just below the videos, and that is the same picture that was used for the auction listing.

[Xringer]

I guess they expect the hubs to bend.?.

Wind turbine

I wonder how they bent it, in the first place?

Just picture this hub with 4" off the OD. Not much metal in the center area at all..



It's hard to estimate, but it seems like there is about 1/2" of steel between
the mounting hole and the 'air vent' holes.

I think this hub would be a LOT harder to bend, if those air-holes were gone.

[jwxr7]

Here's a few things from my emails to the company. At first they said it wasn't a problem and then showed me the story in your link Xringer.
I told them the hub is a little wobbly and asked them at what wind speed can I use this blade/hub set safely while loaded? No answer was given for that.

They did say this...

This is very unusual!!!!! We have sold 200,000 units and you are the ONLY person who is having this problem. I would say the fastest fix would be to remove the blades and put the hub on reversed facing CONE SIDE into the wind.

The blades will need to be flipped of coarse so FLAT SIDE still faces into the wind. Then it should bend back evenly.

THIS should be done under NO Load to make them spin as fast as possible!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! centrifugal force

ALSO weigh the blades and put the two LIGHTEST ones opposite each other on the hub,,, Problem FIXED!

Kim

then this...

Bending back is not a big problem.... Now if it is out of balance that is a problem,,, but very easy to solve.
It is part of the design,,, to be flexible. Their are things more horrible then a blade hitting a pole,,,, like a blades KILLING someone.

This is part of the safety feature.

Kim

Seems like a strong hub would be safer . I plan to furl around 26-27 mph now, so maybe it won't be as big an issue.
I used a gram scale and balanced out the blades using different weight washers. There were a couple that were 6-7 grams heavier than the rest. They were supposed to be a balanced set. I don't know how balanced they need to be, but now they are within a fraction of a gram of each other.

[Xringer]

1 out of 200,000?? It seems like they would want that one back to analyze.
I'm sure most manufactures would want to take a look at it, for QA.

And, "put the two LIGHTEST ones opposite each other on the hub," might be
a good idea, when the whole assembly is balanced. (The same blade doesn't always sink to the bottom).

I agree that a strong hub would be safer.

One question I would ask them:
Did all of those 200,000 hubs, have those 3 big air-holes in them?


After reading the "THE GREAT CONE CONTROVERSY",
Wind turbine cones
I can't really see what good those big air holes in the hub would be,
if you are using a spinner cone.. (Which would block air flow into the holes).


Metal fatigue:
Is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading.

Bend a steel coat-hanger a few times, no problem. But bend it 20 times and it breaks..

[jwxr7]

I was able to tweak the hub so it runs much more true, but still convex. I'll try running it concave forward and see what happens. I painted it and some of the other bare metal parts of the turbine. I put a finl on the tail that should cause it to furl around 27mph. I haven't reassembled or tested anything yet.

I was able to do some Arduinio programming for a simple battery discharge control scenario. I am considering using a battery or batteries in the system, so I can pulse-and-glide the grid tie inverter. Inverters typically run most efficiently when putting out rated power. Then the system can slowly collect low power on typical days that wouldn't normally be enough to turn on the inverter. The Arduino will monitor the battery charge and dump energy into the grid as needed. Another advantage to this system would be the ease of adding other energy sources. I could connect my little 5 watt solar panel (or a pedal generator etc )to the batteries to add more energy to be dumped into the grid.

The barn has a nice new roof now. I have been thinking about tower mounting a little. I know roof mounting is far from ideal and now I don't really want to penetrate the new roofing deck. I have been considering a guyed tower out in the field. I may start with a tower attached to the west gabel end of the barn roof to get some more testing done before going all-out on a guyed tower.

[jwxr7]

I bought and recieved a 500w grid tie inverter. I haven't had a chance to really test it yet. But I did a quick test and got 500w out of it thru my kill-a-watt, with 24v of battery connected to it.

I've pretty well got the arduino system tested and working, just need to do some test witht the inverter in the system.

[Xringer]

Which one did you get? Post the store link please, so I can see the specs..
And some pics would be good too.

[jwxr7]

Originally Posted by Xringer

Which one did you get? Post the store link please, so I can see the specs..
And some pics would be good too.

I bought mine off ebay.
Here's the text from the listing;

NEW Grid Power 500W 12v 110v/240v
For Solar Panel & Wind Hybrid Systems
User Guide:
Installation & Connection
1.1 Red Terminal: to connect positive pole of DC; Black Terminal: to connect negative pole of DC.
AC Socket: to connect grid.
Switch: Power Switch, after the proper connecting, turn on, Inverter start working.
DC Input limits:
Operating Voltage range: 12.5V to 28V
Maximum input Voltage: 28V
Solar Panel: 30W minimum, only use PV panels with maximum power voltage at 17.5V.
Can ONLY connect panels in parallel. DO NOT connect them in series!
Wind Turbine: Rated output voltage 24VDC, Maximum voltage 28VDC
AC Output:
Grid Connection:
220V AC version: 170V-250V, 50Hz
110V AC version: 90V-140V, 60Hz
Island Protection: Automatically disconnect when the grid is tripped
Maximum quantity of Pure Sine-wave Inverters allowed on a main circuit: No limited
LED Indicators:
Red LED on: Input DC voltage is too high or low (less than 12.5V or more than 28V)
Red LED on: Over Heat protection once over 70℃, automatic restart after cooling
down for about 2-10 minutes.
Red LED on: Grid blackout fault
Green LED Flashing: Output power in the state of regulation.
Green LED on continuously: Inverter works normally, constantly max. output power.
Caution:
Please do install the inverter in a ventilated area to avoid over-heating
Clear out any flammable object around the installation
Recommend a maximum output DC input cable size of 4AWG or cables that can handle more than 50A.
Optimal length would be 8m or lower, Longer cables will experience higher voltage drop.
Install in a low humidity and well-ventilated area. Remove All flammable objects.
Connect the inverter to a wall socket with the supplied AC Power Cord
Connect the Solar Panel, Battery or Wind Turbine's DC Supply cables to the DC input
Terminal of the inverter. Wind Turbine installations will require respective charge Controllers and dump loads
1. Description：
l Directly connected to solar panel design（Without battery）
l Angle with high precision auto-detect if it was held 0 Total
l Step directly modulated high-frequency phase
l Pure sine wave output
l Solar luminosity power automatically adapt
l Automatic power locking
l Maximum Power Point Tracking(MPPT)
l Automatically adapt to different load power factor
l Constant current, constant-power design
l Power grid automatically shut down when the output is faulty
l Current limit protection
l Schmitt trigger SPWM Generator(Output Pure sine wave)
l Straight-line with the design
l Multiple stack(Use of multiple machines in parallel)
l Design of high frequency and high conversion rate
2. Electrical Specifications:
Grid-inverter Type 500W
Recommended Maximum PV Power Ppv=720Wp
DC Maximum Input Power PDC.max=600W
DC Maximum Voltage VpvDC30.2VDC
PV MPPT DC Voltage Range Vpv 12.5V~28VDC
Peak Inverter Efficiency ηmax>94%
MPPT Efficiency 99%
PV Maximum Input Current Ipv.max30A
AC Rating Output Power 500W AC
AC Maximum Output Power 550W AC
Reverse Polarity Protection Fuse
AC Normal Voltage Range 90V-140/180~260VAC
AC Frequency 45Hz53Hz/55Hz~63Hz
Inverter Output Current Total Harmonic Distortion THDIAC <5%
Phaseshift <1%
Island Effect Protection VAC;f AC
Inverter Output Shorting Protection Current Limiting
Disaplay LCD and LED
Standby Power Consumption <8W
Nighttime Power Consumption <1W
Ambient Temperature Range -25 ℃~60℃
Ambient Humidity 0~99%(Indoor Type Design)
Waterproof Indoor Type Design
Eelectromagnetic Compatibility EN50081.part1 EN50082.part1
Power Network Disturbance EN61000-3-2
Power Network Detection DIN VDE 126
3. Mechanical Specifications:
Weight 1.3kg/2.866lb
Dimension (L x W x H) 21 x 16.5 x5.8cm
Mounting Wall Mount at base
AC Cable Length 1.8m
Cooling Convection cooled with fan
Display 1 Red and 1 Green LED

[Xringer]

Operating Voltage range: 12.5V to 28V Maximum input Voltage: 28V
Solar Panel: 30W minimum, only use PV panels with maximum power voltage at 17.5V.


That seems to really limit how high you can go with your panels or turbine..
How do you plan to feed this inverter?



AC Output:
Grid Connection:
220V AC version: 170V-250V, 50Hz
110V AC version: 90V-140V, 60Hz

I hope you are getting the 110Vac version.. Since it looks like the 220 is made for a 50 Hz line freq..