Sunny Boy 2000
Technical Description
SB2000-11:EE
- 38 -
SMA Regelsysteme GmbH
•
Failure of the thermally monitored varistors on DC-side
On the DC input side the Sunny Boy is equipped with thermally monitored varis-
tors (plus and minus pole to protective earth each). They are installed in order
to prevent the inverter from being destroyed by atmospheric surge voltages
(thunderstorm etc. invoked electric fields). If the thermally monitored varistors
have triggered for several times (a thermally monitored varistor is the serial cir-
cuit of a varistor and a thermal fuse) they can get defective by not letting any
current pass anymore and therefore not providing the intended safety. This
condition is indicated with the ‘Earth fault’ LED.
It is highly recommended to have qualified personnel exchange the
thermally monitored varistors if necessary.
••••
Determining the Failure
The red LED indicates one of the above mentioned failures. A short descrip-
tion on how to distinguish between these and conduct the appropriate coun-
termeasures is given in the following.
This description is very concise – please stick to the relevant regulations in
chapters 3.3, ‘Electric Connection’ and 4, ‘Commissioning’.
•
Disconnect the inverter from the grid (mains fuse).
•
Disconnect the inverter from all poles of the PV-panel (snap cable connec-
tors)
Wait for at least 30 minutes for the internal voltages to discharge!
•
Open the inverter.
•
Remove the two internal thermally monitored varistors (Fig. 5.2) with an
appropriate screwdriver.
•
Short circuit the connectors 2 and 3 in the connector blocks X2 and X3
(see Fig. 5.2).
