Author Topic: 4' turbine very frustrating! (Read 3470 times)

defed · « **on:** July 17, 2010, 12:04:58 PM »

have a 4' Piggott on a 16' test tower w/ anemometer near the same height just so i can see the actual wind at that position. once the thing is going, it goes pretty well...but the darn thing takes a 15-30 second gust of 15mph to get up to speed! i've have about 10mph avg for the last 3 hrs, but it wasn't making any power (lazy spinning) until i got that good burst. now that it is going, it can survive 6mph for several seconds and not lose its momentum (no charging tho). then when the wind gets back to about 8mph, it will speed right up. this was only a practice model and want to do some tests w/ it and the anemometer before i put up my real tower and make a 10'. i know the 4' has low swept area and is harder to overcome the bearing (whereas a 10' on the same spindle would probably go much easier)...but it is just frustrating having decent 10-14mph winds and see it not be able to start! looking up at the tree tops and seeing them bending horizontal is encouraging tho for the future.

maybe i need a little motor on it to get it up to speed in 8mph, where it will STAY running, just not start!

i should also mention that my anemometer isn't 100% calibrated, but it should be close...so my wind speeds could be a little off. have to take it to work and calibrate it on their VP2.

Rover · « **Reply #1 on:** July 17, 2010, 12:19:39 PM »

Welcome to the world of small (tiny) wind, what you are experiencing is pretty typical. As one that does the same, even my 6' behaves close to what you describe, and my 4' almost exactly . Although neither are axial flux, I'd put it down down to swept area. There are ways to improve start up. but alll with a cost... typically better low end... and the cost of high end (blade changes, # of blades, rewire)

defed · « **Reply #2 on:** July 17, 2010, 12:51:00 PM »

once it got going, it's been running non stop for the last hr, dropping below charging on occasion, but not stopping. the turnigy meter says i had a peak of 5 amps at 140 watts, which is the highest recorded power to date - but i've only had the meter for 2 days. the anemometer showed a max speed of 24mph (not 100% sure how close my calibration is yet).

i think the meter said 16 watt hrs produced in that time and only .675 amp hrs.

i want to try to get to 20' on the test tower, but 18' might be all i can get. i only plan to keep this 4' up for a year while i collect data and work on permits for my real tower. if that is approved, i will begin building a 10'. i am at least happy that the 4' works as well as it does at 16', can only mean better things for a bigger turbine at a better height. just wish it started up easier.

Rover · « **Reply #3 on:** July 17, 2010, 12:56:16 PM »

Height means (at least for me, numerous trees, etc, I only have a directional wind window) everything (or almost) ... you are low to the ground and have turbulence all over the place.
Glad to see you did make some power

defed · « **Reply #4 on:** July 17, 2010, 01:56:13 PM »

right, i figure 15mph wind at 16ft is not the same at 15mph winds at 50 or 100ft due to the turbulence. i used the test tower because it was already there, and to get the permanent free standing tower, i need a permit and 10-12yds of concrete in the ground to hold it up. figure it would be better to do some testing before i pour all that concrete. that will be more $ than the tower and turbine combined probably. i have 3 sections of 20'...but i am only going to use 2 at first, w/ a 10' stub for 50'. i could get 70' later if everything goes well w/ the 50'.

defed · « **Reply #5 on:** July 17, 2010, 02:40:44 PM »

hit 6 amps and 170 watts at approx 25mph.

defed · « **Reply #6 on:** July 17, 2010, 04:00:08 PM »

the wind is really going now. 7 amp and 206 watt peak...somewhere around 26mph. almost saw it fully furl a cpl of times, and partial furling often. hard to know at what speed it furls because of the small lag on the speedo update, but it appears to begin to furl at 5 amps. i'm guessing it would have been close to full furl at the 7 amps when it broke 200 watts.

defed · « **Reply #7 on:** July 21, 2010, 03:50:21 PM »

new high output today while i was at work...8 amps at 240 watts!

Bruce S · « **Reply #8 on:** July 22, 2010, 02:02:33 AM »

Quote from: defed on July 21, 2010, 03:50:21 PM

new high output today while i was at work...8 amps at 240 watts!

PSA for you

I think you're hooked !!

Have fun too!!
Bruce S

defed · « **Reply #9 on:** July 22, 2010, 06:08:37 PM »

well, hit a new peak output...10 amps at 303 watts....the thing must have been screaming.

bj · « **Reply #10 on:** July 23, 2010, 12:06:36 AM »

Absolutely no doubt. Hooked. I know the feeling.

taylorp035 · « **Reply #11 on:** July 23, 2010, 09:39:58 AM »

Wow, 303 watts out of a 4'

My record was 173 watts and that must of been a good 30 mph gust.

ghurd · « **Reply #12 on:** July 23, 2010, 09:45:34 AM »

I think some of these things just need to run a while before they get "broke in".

Is it starting easier, in less wind?
G-

jlt · « **Reply #13 on:** July 23, 2010, 10:23:53 AM »

I have a 5ft gen using a 90v dc motor and it had the same problem starting .I put on three short blades between the other blades. they are only about a foot long. it starts much better now. and the top end power is about the same.mine furls at about 5 amps . the motor is only rated for that much.

defed · « **Reply #14 on:** July 23, 2010, 04:57:43 PM »

Quote from: ghurd on July 23, 2010, 09:45:34 AM

I think some of these things just need to run a while before they get "broke in".

Is it starting easier, in less wind?
G-

not really...it's either....stiff bearings, not clean wind due to too much turbulence at this low height, mis balanced blade...or some combo of all 3!

i'm still happy w/ how it works once it's going. made .5Kw so far this week.

defed · « **Reply #15 on:** July 23, 2010, 04:58:46 PM »

Quote from: jlt on July 23, 2010, 10:23:53 AM

I have a 5ft gen using a 90v dc motor and it had the same problem starting .I put on three short blades between the other blades. they are only about a foot long. it starts much better now. and the top end power is about the same.mine furls at about 5 amps . the motor is only rated for that much.

interesting...any pics?

i hope to NOT have this problem if/when i get my 10' up.

defed · « **Reply #16 on:** July 23, 2010, 05:01:39 PM »

Quote from: taylorp035 on July 23, 2010, 09:39:58 AM

Wow, 303 watts out of a 4' My record was 173 watts and that must of been a good 30 mph gust.

i'd say it was probably a 30mph gust when i hit 300 watts. it only lasted a brief moment, so i don't think it had time to furl. under normal operations, it looks like it starts to furl at 5 amps or so, and i've seen it pretty near full furl at 7 or 8 amps, but it doesn't last long before it drops out. if it was up high, it would probably not UN-furl!

defed · « **Reply #17 on:** August 05, 2010, 12:38:20 PM »

didn't have my wind speedo hooked up, so don't know what wind speed we had, but when i checked my turnigy meter today it said:

476w @ 16.5a......HOLY COW!

i don't even know when we got winds that high!

Bruce S · « **Reply #18 on:** August 05, 2010, 01:12:57 PM »

Quote from: defed on August 05, 2010, 12:38:20 PM

didn't have my wind speedo hooked up, so don't know what wind speed we had, but when i checked my turnigy meter today it said:

476w @ 16.5a......HOLY COW!

i don't even know when we got winds that high!

careful

too much FUN and someones going try and tax you on it

All good fun tho.
Keep it up!!
Congrats !!
Bruce S

defed · « **Reply #19 on:** August 05, 2010, 01:19:00 PM »

thanks. while i work on getting my paperwork together for the permit on my 50' tower (for 10' turbine) i've been looking into adding some solar. months of research to understand the axial flux stuff, now i'm starting all over w/ solar.

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Author Topic: 4' turbine very frustrating! (Read 3470 times)