Generac Power Systems PWRcell Reference Manual page 53

Section 8 PWRcell ATS
Utility Source Voltage Failure – Inverter Only Configuration
The inverter senses that utility voltage falls below a voltage dropout set point via N1 and N2. When the line interrupt
drops below specifications, the inverter responds to the utility failure and will initiate transfer by grounding Wire 23. The
inverter supplies voltage to the switch through E1 and E2.
Inverter voltage from E2 is connected to Terminal 4 of the controller. Because the switch is in the UTILITY position, the
XB1 limit switch contacts are closed. This connects E1 through the closed XB1 limit switch to C2 terminal 2. The
closing coil requires a minimum of 190 VAC from both phases of the supply to activate. Even though E1 is connected
through the XB1 contact, the coil will not energize until the internal controller K5 relay contacts close (Wire E2 to the
open TR contact).
As soon as the inverter controller grounds Wire 23, the internal relay standby contacts close (UTILITY contacts open)
and the switch powers to the STANDBY position.
013087
Figure 8-8. Utility Source Voltage Failure
Diagnostic Repair Manual 49