Cell phone towers and high winds?
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Topic: Cell phone towers and high winds?
Posted By: DougG
Subject: Cell phone towers and high winds?
Date Posted: 13 Mar 2019 at 5:26pm
| With this BOMB CYCLONE going thru Mo tonight and wins expected at 60 mph , was thinking about how much wind can a cell phone tower take? Cable kind and free standing? |
Replies:
Posted By: ac fleet
Date Posted: 13 Mar 2019 at 5:52pm
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If they are designed properly, they should stand 150 mph. Our wind turbines are rated at that. ------------- http://machinebuildersnetwork.com/ |
Posted By: DougG
Date Posted: 13 Mar 2019 at 5:59pm
| Then the blades start flying off!? |
Posted By: Hubert (Ga)engine7
Date Posted: 13 Mar 2019 at 8:18pm
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Those towers can take a lot of wind if designed properly and they don't put too junk on them. The metal framework doesn't catch a lot of wind. Bet those wind turbines are going crazy in high winds. I wouldn't want to be around when they go to slinging off blades though. ------------- Just an old country boy saved by the grace of God. |
Posted By: Michael V (NM)
Date Posted: 13 Mar 2019 at 8:53pm
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https://m.facebook.com/story.php?story_fbid=2570636472953263&id=100000208058544" rel="nofollow - https://m.facebook.com/story.php?story_fbid=2570636472953263&id=100000208058544 Here ya go..this is in NM, close to House , south of Tucumcari |
Posted By: Michael V (NM)
Date Posted: 13 Mar 2019 at 8:55pm
Darnit..can't get the link to work..but shows a wind gen tower blown over by high winds |
Michael V (NM) wrote:Posted By: LouSWPA
Date Posted: 13 Mar 2019 at 9:43pm
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I think they can 'feather' those props in high wind ------------- I am still confident of this; I will see the goodness of the Lord in the land of the living. Wait for the Lord; be strong and take heart and wait for the Lord. Ps 27 |
Posted By: steve(ill)
Date Posted: 13 Mar 2019 at 9:59pm
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turbine only turns at a given RPM... if it starts to go faster, then rotate the blade angle , apply brakes, or shut it down and lock it... ------------- Like them all, but love the "B"s. |
Posted By: DaveKamp
Date Posted: 13 Mar 2019 at 11:47pm
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Correct- the big turbines are basically all 'synchronous' generators... the blades turn at one speed, they're geared up to a generator who's windings are directly driving AC mains. In order for the blades to turn FASTER, the line frequency MUST increase, but in order for a generator to do that, it would have to be capable of putting out enough current to accept the entire grid's load... an infinite load. The blades have pitch control, basically to optimize lift to provide the most output possible at any given wind speed... and when wind speed exceeds the structure's design capacity, it feathers the blades out, applies brakes, and brings it to a stop. Cell towers come in three flavors- a vertical lattice-type tower (straight, like a broadcast tower) with guy wires, a tubular self-supporting, and a tapered lattice-type. All three types are installed with wind survival criteria that includes loading of antennas, cabling, beacons, etc., suitable for the locality. Coastal areas are set up for hurricane survival, while inland flats are designed for high wind. Northerns include idc loading ratings as well. Straight vertical towers with guy wires, they equip the tower with torque arms to keep the tower from twisting under wind, they'll take immense windload. Tubular towers do really well, generally they'll flex a bit like a fishing pole. Since cellular antenna arrays need to be very stable in direction and azimuth, companies will typically use tower structures WAY more rigid than normal, and as a result, the windload ratings are incredibly conservative. Three legged lattice tapered towers, similar story- geometry keeps them really rigid. A common type like this is the Rohn SSV, I have one, legs are placed on 18 foot centers, legs are 10" diameter 1/2" wall, tapers to 8 ft centers 6" OD tube... five sections totalling 100ft tall, formerly used at a microwave relay site... when I stand up at the top, I can throw my weight around as hard as I want, it doesn't budge at all.  ------------- Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest. |