Checking The Function Of The Varistors - SMA SUNNY MINI CENTRAL 4600A Installation Manual

SMA Solar Technology AG
9.3.2 Checking the Function of the Varistors
Varistors are wearing parts. Their functional efficiency diminishes with age or following repeated
responses as a result of overvoltages. It is therefore possible that one of the thermally monitored
varistors has lost its protective function, and thus the red LED is lit.
Position of varistors
You can determine the position of the varistors using the illustration below.
Observe the following assignment of the
terminals:
• Terminal A: outer terminal (varistor
connection with loop [crimp])
• Terminal B: middle terminal
• Terminal C: outer terminal (varistor
connection without loop [crimp])
Check the function of the varistors as described below:
1. Open the inverter as described in section 7.2 "Opening the Inverter" (page 55).
2. With the aid of a multimeter, determine for both
varistors in the installed state whether a conductive
connection exists between connectors B and C.
Result
☑ There is a conductive connection. There is probably a different error in the inverter.
Installation Manual
Measure
• Contact the SMA Service Line
(see section 13 "Contact" (page 86)).
SMC46-60A-IA-IEN120471
Troubleshooting
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