William,

The rack in your photo appears to support modules that are not properly sized
for that particular DPW unit. They appear to be fastened to the rack at their
third points rather than their quarter points. I've never seen that before. All
the modules I've seen have been predrilled near their quarter points and the
manufacturer's instructions specify mounting dimensions. If the rack used
improperly, I feel it is unfair to DPW to add your link without an explanation.

Dick Ratico
Solarwind Electric

--- You wrote:
http://millersolar.com/MillerSolar/case_studies/Wind_damage/_wind_damage.html

Miller Solar

> On Apr 22, 2014, at 6:52 PM, john <cvsolar@aol.com> wrote:
> 
> Dave,
>     I just had my first ever failure of a DPW TPM-8 with 8 SolarWorld 260's on
it.  I installed it late last fall and the customer called last week to say that
it is on the ground.  It turned out that the nut on the main pivot bolt worked
its way off, the bolt then worked its way out of one of the ears and then the
other ear bent 90 degrees and let the bolt slide out.  The whole rack then fell
to the ground snapping the adjusting bar off.  The rack landed face down and the
corner panel broke from hitting the ground first and two more both hit the
concrete base and broke.  The other five panels were OK and the rack parts are
all OK except for the adjusting arm and the cap.  The main bolt holes in the
strong-back are a little roughed up.   We had  torqued the main bolt when we
installed it and then the customer adjusted it to spring angle a few weeks ago. 
He said he didn't touch the main bolt.  The only thing we noticed on these
current racks was the appearance of never-seize on the main bolt.  I would
suggest that everyone in windy areas should check the bolt torque often.  I have
been told by notable mechanical engineers that the only way to assure that the
nut does not loosen is to use lock-tite. We used nyloks on all the racks we
built in 2009 - 2011.  We started buying DPW racks again when we discovered that
shipping was cheaper than renting space for a rack shop.
> 
> PS   Dave,   Plan on coming to SolarFest 2014.  It's the 20th anniversary year
and we are going to celebrate the good old days of solar. (as well as the latest
and greatest.  I still remember when I was the Newbee. Any other wrenches, I can
get you free tickets (worth $75) contact me off-list.
> 
> John Blittersdorf
> Central Vermont Solar & Wind.
> email  CVSOLAR@AOL.COM
> 
--- end of quote ---

