Installation & Operations Manual SunDial
™ Series PV Inverter
Product Models: 30PV; 30PVF; 30PV+S; 30PVF+S
MAN-00117, Rev C
Page
22
of
31
Ground-Referenced Combiner
The 30PV and 30PV+S SunDial
™ Inverters utilize a circuit that references the negative
leg of the combined PV Strings to earth ground via Ground Fault Detection Interface
(GFDI) circuit, which senses DC fault currents. The 1 A fault fuse located on the
DC2/DC3 Interconnect Board will open whenever a ground fault on DC COM of > 1 A is
encountered. The fuse must be replaced; the fault condition must be cleared; and the
Inverter AC power must be cycled, to clear the Inverter
’s internal GFDI fault. This is
known as a “lock-down” fault, requiring a site visit to clear.
The ground-referenced Combiner utilizes six (6)
“touch-safe” string fuses located on the
positive leg of each string input, the six (6) negative String legs are not fused.
The combined positive legs are connected internally to DC2 (T7) on the DC2/DC3
Interconnection Board, which is located in the main enclosure, above the Combiner.
The combined negative legs are connected internally to DC COM (T8) on the DC2/DC3
Interconnection Board.
A PV arc-fault detection circuit is mounted above the fuse holders, with its detection
toroid mounted to the immediate right. A detected arc-fault is a lock-down fault
condition, requiring a site visit to clear. See Section 8.0 for more fault details.
Floating Combiner
The 30PVF and 30PVF+S SunDial
™ Inverters utilize an IMI circuit for the detection of
ground faults. Describing the operation of this fault detection circuit is beyond the scope
of this manual, however, like the GFDI circuit described above, an IMI-detected ground
fault on DC COM is a lock-down fault requiring a site visit to clear.
Figure 8: Internal View of Floating Combiner
