Automatic Transfer Switch Control (Mains Failure)

The DGC-2020HD has the ability to detect a mains failure via a single- or three-phase bus input. A mains

failure is established when any one of the following conditions are met:

• Any phase of bus voltage falls below the dead bus threshold

• Any phase of bus voltage is unstable due to overvoltage or undervoltage

• Any phase of bus voltage is unstable due to overfrequency or underfrequency

At this time, the DGC-2020HD starts enough generators to pick up the anticipated load and transfers the

load to the generators when predetermined conditions are met. The DGC-2020HD implements open or

closed breaker transitions to and from the mains. When the mains returns and is considered stable, the

DGC-2020HD transfers the load back to the mains and stops the engines. During closed breaker

transitions, the optional Auto Synchronizer synchronizes the generators to the mains before transferring

the load from generator power to utility power.