Checking The Function Of The Varistors - SMA SUNNY BOY 3000TL Service Manual

6 Checking the Function of the Varistors

6 Checking the Function of the Varistors
Figure 2: Varistors inside the inverter
Destruction of 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 PV systems with a high risk of overvoltages.
• Do not recommission the inverter until the defective varistors have been replaced.
Destruction of the measuring device due to overvoltage
• Only use measuring devices with a DC input voltage range of 1,000 V or higher.
Check the function of each varistor as described in the following:
Procedure:
1.
Danger to life due to high voltages
• Disconnect the inverter from all voltage sources (see Section 2.2, page 7).
2. Loosen the screws on the upper enclosure lid using an Allen key (AF 4) and remove the
enclosure lid.
3. Position the insertion tool in the clamping
contacts of the connecting terminal plate.
4. Remove the varistor from the connecting terminal plate.
22 SB30-60TL-21-SG-en-11
SMA Solar Technology AG
Service Manual