SMA Solar Technology AG
Troubleshooting
Installation Manual
WB33-38-IA-IEN120940
65
9.3.2 Checking the Function of the Varistors
Varistors are wear parts. Their functional efficiency diminishes with age or repeated strain as a result
of overvoltages. It is therefore possible that one of the thermally monitored varistors has lost its
protective function.
You can check the function of the varistors as follows:
1. Open the inverter as described in Section 7.2 "Opening the Inverter" (page 48).
2. Use a multimeter to check that in each of the
installed varistors there is a conductive connection
between terminals B and C.
Position of the varistors
The position of the varistors can be located with the help of the diagram below. Note the
following assignment of the terminals:
• Terminal A: outer terminal
(varistor connection
with crimp
)
• Terminal B: middle terminal
• Terminal C: outer terminal
(varistor connection
without crimp
)
Result
What to do
There is
a conductive
connection.
There is presumably a different error in the inverter.
1. Close the inverter as described in Section
7.3 "Closing the Inverter" (page 50).
2. Contact the SMA Service Line.
