[RE-wrenches] Racks, wind

[frenergy]

Also, gotta say Jeff is building very high quality TOP racks. We've 
installed 7-8 of them since his "departure" from DPW, now Preformed Line 
Products.  Welds, materials, powder coating are top notch.  Right at 
first, as you can imagine getting started again, there were a couple 
small details that were a little wonky but they seem to have it wired 
now.  Ship times might be a little better too.

             William, curious how old some of the wind ravaged racks 
are?  I haven't seen that 2X2" material being used for awhile on a rack 
that size.  I used to have some problems with snow when they were using 
that 2X2" square steel tubing...that was several years ago, like 10?

Bill

Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net


On 1/10/2017 8:54 PM, Jay wrote:
> I can't find the link to Jeff randles new rack company?
>
> Can someone help me out
>
> Thx
> Jay
> Peltz power.
>
> Sent from my iPhone
>
>> On Jan 10, 2017, at 8:31 PM, Ray Walters <ray at solarray.com> wrote:
>>
>> Hi William;
>>
>> Your link had a glitch,  I think this should be it?
>> http://www.millersolar.com/MillerSolar/case_studies/Wind_damage/_wind_damage.html
>>
>> We have DP&W's high wind option which bumped the pole size from 4" to 6" along with heavier hardware throughout.  I haven't been to the site yet, but the techs were reporting just the module failed and the rack is still good.  I'm going up next week and I'll try to figure this out.  This site also has a funnel effect as you mentioned.  Higher ridges to the North and South, and this smaller peak between with our rack almost right at the top.
>> Roof mounts actually do seem to be much better; the wind doesn't get behind it, and if the array is set back from the edge,  the side edge of the array isn't getting pummeled.
>> Our failure occurred with an angled wind, not perpendicular.   Your rack failures look also to have had uneven loading: the way it twisted that top rail off. I almost wonder if these racks aren't hitting some resonance that's causing the rack to twist and torque back and forth repeatedly.  You can grab the corner of the array and "pluck" it, then watch it bounce back and forth: that's the simple way to determine its harmonic resonance.
>>
>> R.Ray Walters
>> CTO, Solarray, Inc
>> Nabcep Certified PV Installer,
>> Licensed Master Electrician
>> Solar Design Engineer
>> 303 505-8760
>>
>>> On 1/10/2017 6:26 PM, William Miller wrote:
>>> Ray:
>>>
>>> I can't say I have a solution to your problem, but I can share some photos
>>> of two similar failures in case you can glean any information from them.
>>> See:
>>> http://www.millersolar.com/MillerSolar/case_studies/Wind_damage/_wind_dama
>>> ge.html
>>>
>>> The first failure is a Zomeworks.  On the same exact spot we tried a DPW
>>> TOP.  Neither could withstand a funnel effect provided by the topography.
>>>
>>> At the same location we installed a roof mount as well that has never
>>> failed (to my knowledge, we don't service that customer anymore).
>>>
>>> I think if you have terrain that is tilted in the correct direction a
>>> mount that hugs the ground is best.  That is a lay opinion, however.
>>>
>>> William
>>>
>>>
>>>
>>> Lic 773985
>>> millersolar.com
>>> 805-438-5600
>>>

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