Replacing the varistors
SMA
Technologie AG
Page 36
SB2500-11:SE2006
Installation Guide
5.
Repeat points 3 and 4 for each string.
If you found a ground contact, it is probably not necessary to replace the
varistors. Instead, make sure the ground fault is fixed. Generally the PV
generator's installation engineer should be hired for this job. In this case
continue as described under point 10, but without reconnecting the faulty string.
Protect its DC plug against accidental touch contact (e.g. by fitting the protective
caps or using sufficient high-voltage insulating tape).
If you did not find any ground contact in the PV generators, it is likely that one
of the thermally monitored varistors has lost its protective function. These
components are wearing parts. Their functioning diminishes with age or
following repeated responses as a result of overvoltages. You can now check
these varistors in the following way, paying attention to the safety information
in section 2 "Safety information" (page 9).
6.
Remove the screws that secure the lid and remove the lid from the Sunny Boy
2500. Disconnect the PE connection from the lid. Make sure that no voltage is
present.
7.
Using a continuity tester, check all the varistors to see if there is a conducting
connection between connectors 2 and 3. If there isn't, then that varistor is not
working. The positions of the varistors in the Sunny Boy 2500 can be seen in the
diagram in section 3.1 "Unit description" (page 11).
8.
Replace the varistor concerned with a new one
as shown in the drawing to the right. Ensure the
varistor is installed the right way round! If you
do not receive a special tool for operating the
terminal clamps with your replacement
varistors, please contact SMA. As an
alternative, the terminal contacts can be
operated using a suitable screwdriver. Since the
failure of one varistor is generally due to factors
that affect all varistors in a similar way
(temperature, age, inductive overvoltages), it is
highly recommended that you replace both
varistors, not just the one that is obviously
defective. The varistors were specially
manufactured for use in the Sunny Boy 2500
and are not commercially available. They must
be ordered directly from
SMA
Technologie AG
(SMA order code: SB-TV4).
Summary of Contents for SUNNY BOY 2500
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Page 6: ...Table of Contents SMA Technologie AG Page 6 SB2500 11 SE2006 Installation Guide ...
Page 8: ...Foreword SMA Technologie AG Page 8 SB2500 11 SE2006 Installation Guide ...
Page 10: ...Safety information SMA Technologie AG Page 10 SB2500 11 SE2006 Installation Guide ...
Page 38: ...Replacing the varistors SMA Technologie AG Page 38 SB2500 11 SE2006 Installation Guide ...
Page 44: ...Contact SMA Technologie AG Page 44 SB2500 11 SE2006 Installation Guide ...
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