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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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very low wind and wind turbines turning
Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph?
Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? |
#2
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very low wind and wind turbines turning
misterroy wrote
Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Nope, you are wrong about that. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? The wind can be surprisingly variable, particularly when there is hardly any wind at all. Just been out on a mates 2 ton yacht, testing the launching system and its surprising how variable the wind can be. |
#3
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very low wind and wind turbines turning
On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote:
Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. -- Cheers Dave. |
#4
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very low wind and wind turbines turning
On 08/08/2017 00:18, Dave Liquorice wrote:
On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. Oh dear, these must be well and truly f**ked: http://www.bbc.co.uk/news/uk-england...shire-27393177 They haven't moved in years! |
#5
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very low wind and wind turbines turning
On Tuesday, August 8, 2017 at 12:18:41 AM UTC+1, Dave Liquorice wrote:
On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. -- Cheers Dave. There is a wind farm here and a few years ago there was storm force wind, and then a power cut. The wind changed direction, still storm, and because there was no power the turbines could not turn the blades to the desired angle, the bearings were finished by the time the storm had passed. They turbines were only four months old. |
#6
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very low wind and wind turbines turning
On Tuesday, August 8, 2017 at 5:09:32 AM UTC+1, misterroy wrote:
On Tuesday, August 8, 2017 at 12:18:41 AM UTC+1, Dave Liquorice wrote: On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. -- Cheers Dave. There is a wind farm here and a few years ago there was storm force wind, and then a power cut. The wind changed direction, still storm, and because there was no power the turbines could not turn the blades to the desired angle, the bearings were finished by the time the storm had passed. They turbines were only four months old. There are three turbines up from my house, somewhere between 0.5 and 1 MW, there is no wind and they are turning at 17 rpm. There is also a 50kW turbine which is stopped. Since the load on the 50kW turbine is so much smaller, it does not need to turn. Would that be correct? |
#7
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very low wind and wind turbines turning
"misterroy" wrote in message ... On Tuesday, August 8, 2017 at 5:09:32 AM UTC+1, misterroy wrote: On Tuesday, August 8, 2017 at 12:18:41 AM UTC+1, Dave Liquorice wrote: On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. -- Cheers Dave. There is a wind farm here and a few years ago there was storm force wind, and then a power cut. The wind changed direction, still storm, and because there was no power the turbines could not turn the blades to the desired angle, the bearings were finished by the time the storm had passed. They turbines were only four months old. There are three turbines up from my house, somewhere between 0.5 and 1 MW, there is no wind and they are turning at 17 rpm. Its more likely that there is more wind up there than at your place. Unlikely to be worth running them at 17 rpm for the bearings. There is also a 50kW turbine which is stopped. Since the load on the 50kW turbine is so much smaller, it does not need to turn. Would that be correct? More likely its got a different bearing design which doesnt need to always be turning. |
#8
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very low wind and wind turbines turning
Well maybe some are broken in the brake department. Seriously though, I
suspect each has a detector and uses that to decide. There has to be something that turns them and if the wind is that something I see no harm in them rotating even if off line. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please! "misterroy" wrote in message ... Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? |
#9
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very low wind and wind turbines turning
On 07/08/17 21:56, misterroy wrote:
Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? More like below 5mph Id say. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Because motors keep them turning to save the bearings from flat spots. -- No Apple devices were knowingly used in the preparation of this post. |
#10
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very low wind and wind turbines turning
On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy
wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? It could be the wind gradient: the wind speed drops off quite a bit as you get close to the ground. So depending on how high the blades are, the wind velocity could be higher than at ground level. |
#11
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very low wind and wind turbines turning
On Tue, 8 Aug 2017 01:08:20 +0100, Fredxxx wrote:
On 08/08/2017 00:18, Dave Liquorice wrote: On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Varies. Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? Those blades are big, heavy and flexable. They motor them round to prevent damage to the bearing(s) and to not have the blades take a set. If you see a turbne going slow watch a blade and how much it flexes as it goes past 12 o'clock. Oh dear, these must be well and truly f**ked: http://www.bbc.co.uk/news/uk-england...shire-27393177 They haven't moved in years! I reasonably frequently go past them and noticed they were finally working. Seems as though the radar issue has been resolved: https://www.s****er.co.uk/news/news-...wer-full-time/ -- AnthonyL |
#12
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very low wind and wind turbines turning
On Tuesday, August 8, 2017 at 12:29:58 PM UTC+1, Caecilius wrote:
On Mon, 7 Aug 2017 13:56:27 -0700 (PDT), misterroy wrote: Am I correct in thinking that large wind turbines do not produce power when the wind speed is below 12mph? Why on some days do they stop altogether and others they keep turning, even though there is hardly any wind at all? It could be the wind gradient: the wind speed drops off quite a bit as you get close to the ground. So depending on how high the blades are, the wind velocity could be higher than at ground level. there are calculators on the web for the wind gradient, and the effect is quite small, at low speeds anyway. |
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