SMA SI-TB-BOX-10 - Manual (Page 20)

4 Product Description SMA America, LLC
20 SI_TDBOX-IA-eng-IUS122211 Installation Manual
4.6 Overload Protection
The overload protection protects the autotransformer against damage from overheating or a short
circuit. The overload protection identifies overheating or a short circuit by monitoring the currents in
the autotransformer. If currents become too high, the overload protection is tripped with a predefined
time delay. The time delay prevents tripping of the overload protection during brief switch-on current
peaks.
Figure 6: Overview of the overload protection
Position Description Explanation
A Switch position "1" The overload protection is in its normal operating state.
Current is flowing through the primary side and the secondary
side of the autotransformer.
B Switch position "0" The overload protection has been tripped. The current flow is
interrupted on the secondary side of the transformer.