[RE-wrenches] Solar World Wind Damage

[Ray Walters]

Hi Daryl;

I wonder if the DP&W rack is allowing some bending or torqueing of the 
module frame, that over time with thin aluminum causes  metal fatigue, 
cracking, and finally total failure.   Funny both of our isolated 
failures involved the same rack.  Also, I did more sluething and these 
modules were the thinner (31 mm) 2.5 frame from Solarworld.  They've 
since gone back to a 33 mm frame; version 4.0. I also found in the specs 
that the back pressure these modules can handle is 64 PSF, so I can't 
believe we exceeded that.  In dry, cold air at 9000 ft elevation, even 
winds over 100 mph aren't half that pressure.

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 1/10/2017 4:38 PM, penobscotsolar at midmaine.com wrote:
> Hi Ray,
>     I don't have much advice, but I can tell you that we have a couple of
> ground mounted arrays at a local college (along the ocean) on the same
> DPW high wind rated racks. The college chose to buy Chinese modules
> from a competitor instead of my recommendation and one of the modules,
> after about three years of being installed, gave way the same way,
> literally ripping the washers and hardware through the thin aluminum
> frame. I did tell them when I did the installation that they should
> check every few years that all hardware was tight, as wind, over time,
> vibrates the frame and I feel better when the client watches their
> array for weak points. It is possible over time that the hardware
> worked free a bit and allowed the wind to do what it did. Not sure, but
> I've only seen it this one time in 29 years. We always torque our
> hardware to DPW specs.
>
> Daryl
>
>
>> Greetings All;
>>
>> I just had the dreaded call from one of my higher profile commercial
>> clients: a remote radio repeater station had modules ripped off the
>> frame by high winds.
>> Two  SW285s were damaged.  The wind was strong enough to rip right
>> through the aluminum side rails.  We had used the proper stainless 1/4"
>> bolt hardware with washers on the inside, etc.  All the hardware was
>> still tight, it just tore the aluminum past the washers.  This is not a
>> top down clamp system, but uses bolts through the mounting holes on the
>> back of the module.  This was all on a DP&W rack with high wind option.
>> In 20 years in business, I've never seen that happen.  Is there a
>> contact at Solar World?  I'm not getting through on the tech support
>> line I have.
>> First, I need to know what the wind rating is on the modules blowing
>> from the back side, and
>> Second, a suggested fix for the remaining modules.
>> One module was completely ripped from the frame and thrown 30 yds (total
>> destruction), a 2nd one has cracks in the Aluminum, but has not let go
>> yet.  I was thinking of adding some angle aluminum on the inside to beef
>> it up.  IMHO, the frames are pretty thin aluminum compared to older
>> modules.  I'll share some pics when available.
>>
>> As always thanks in advance for your comments,
>>
>> --
>> R.Ray Walters
>> CTO, Solarray, Inc
>> Nabcep Certified PV Installer,
>> Licensed Master Electrician
>> Solar Design Engineer
>> 303 505-8760
>>
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