Torque for Sunny Boy screws [RE-wrenches]

[John Berdner]

Wrenches: 

I think the error occurred in translation from N m to inch lbs.
The "why" is not all that important but we have sent the information
back to SMA DE and they are changing it for the next revision of the
manual.

Most importantly DO NOT try to torque the dc input and ac output
terminals to 35 inch lbs or they will break. 12 to 15 inch lbs seems to
be about right but I am checking with Germany to get the manufacturer's
specs for the terminal blocks.  I'll do another post when I get the
straight poop.

On the dc side it is not so critical since you have 2 built in spares.  
One thing to note: If you think one snapped on the dc side go ahead and
move the dc wire over to another block.  If it snapped you will probably
have to cut the wire flush at the block and re strip it to insert it
into the next position.  I suggest this because we have seen a couple
inverters where the screws are snapped and the connection failed to
heating. I don't think this is a significant issue but better to take a
couple extra minutes while you are standing there "just in case". 

On the ac side there are no spares so if you snap one neither you nor I
will be happy.  So much hassle for such a stupid little error. Arrrgh!!

If you have any questions or if I may be of any further assistance,
please do not hesitate to contact me.

Best Regards,

John Berdner

SMA America, Inc.
12438-C Loma Rica Road
Grass Valley, CA  95945
530.273.4595 - Tel
530.274.7271 - Fax



-----Original Message-----
From: mlafferty at universalenergies.com
[mailto:mlafferty at universalenergies.com] 
Sent: Wednesday, May 28, 2003 06:31 PM
To: RE-wrenches at topica.com
Subject: RE: Penetration free standing seam clamps [RE-wrenches]

Nick L Wrote:

>If anyone thought it was important enough to go out and buy a 
torque driver to properly torque the Sunny Boy AC and DC terminals 
ignore the manual. 35 in. lbs will break the screw, the only torque I 
had success with was about 15 in.lbs.

First of all, Nick, KUDO's for doing the right thing, installing with
integrity, and following up by letting us all know your results!  

I get somewhat anal about things, too.  In my case, it's from a
perspective of observation and learning to promote efficiency.  For
instance, I learned a long time ago that everybody doesn't have the same
"feel" about the torque of a nut/bolt.  For that matter, they don't
always have a concept of the different characteristics of the materials
they are working with, like iron vs. stainless steel.  For these
reasons, you cannot trust the "feel" or judgement therof to just
anybody.  Manufacturers provide specs for us.  Tool manufacturers
provide tools for us to use in meeting those specs.

It is my observation and opinion that SMA has done an excellent job,
overall, in providing quality manuals and superb support.  Nobody's
perfect, never will be.... No matter how many different torque
wrenches/drivers they buy!  My guess is that the 35 in. lbs. vs. 15 in.
lbs. thing is most likely due to a failure to translate "metric to
American".... i.e. "mm/kg" to "inch/pound".  John B?

Pray for No Tan Lines!

Matt Lafferty
Universal Energies Institute
mlafferty at universalenergies.com
(916) 422-9772
(916) 628-7694 Cell
(916) 914-2247 Fax
www.universalenergies.com

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