Replacing Dc Varistors - SMA Sunny Boy 3000TL-US Installation Manual

SMA America, LLC

11.5 Replacing DC Varistors

In regions where electrical storms or other DC overvoltages frequently occur, the DC varistors lose
their functionality if the PV system is not equipped with additional overvoltage protection. In such
cases, SMA recommends replacing DC varistors with new ones after an operating period of 10 years
in order to ensure that the functionality of the DC varistors remains at a constant level.
Order new varistors directly from SMA (for order numbers, see Page 83).
Damage to the inverter due to overvoltage
If varistors are missing, the inverter is no longer protected against overvoltage.
• Do not operate the inverter without varistors in plants with a high risk of overvoltages.
• Only recommission the inverter after you have replaced the defective varistors.
1. Disconnect the inverter and the DC Disconnect from voltage sources (see Section 10).
2. Insert the insertion tool into the contacts of the
connecting terminal plate.
3. Remove the varistor from the connecting terminal
plate.
4. Insert the new varistor into the terminal. The labels
of the varistor must face to the right at the inside of
the inverter.
Installation Manual
11 Troubleshooting
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