Automatic standby with (Closed Transition) return operation:

• Time delayed control sensor detects if a utility outage has occurred.
• When the timer expires, the generator set is automatically started and brought up to speed and voltage.
• Utility circuit breaker opens and generator circuit breaker closes (after adjustable time delay) so that the generator supplies power to the site load.
• When a healthy utility is connected for a set time delay, and the generator is synchronized with the utility, the generator circuit breaker shall open within 100ms, restoring normal power.

Automatic standby with (Open Transition) return operation:

• Time delayed control sensor detects if a utility outage has occurred.
• When the timer expires, the generator set is automatically started and brought up to speed and voltage.
• Utility circuit breaker opens and generator circuit breaker closes (after adjustable time delay) so that the generator supplies power to the site load.
• When a healthy utility is connected for a set time delay, the generator breaker opens and the utility breaker closes, restoring normal power.

Automatic standby with (Soft loading/Unloading) operation:

• Time delayed control sensor detects if a utility outage has occurred.
• When the timer expires, the generator set is automatically started and brought up to speed and voltage.
• At that time, the utility circuit breaker and the designated feeder breakers shall open, and generator circuit breakers shall close (after adjustable time delay). The synchronizing circuit breaker of the first available generator closes to a dead bus. At this time, the generator is supplying power to the site load.
• When a healthy utility is connected for a set time delay, the soft close transition of the load to the utility shall begin.
• The generator bus synchronizes with the utility source. Close the utility circuit breaker once they’re in sync. At this time, soft unloading of the generator set shall begin.
• When the genset loads are gradually reduced to the level of the unload trip, setpoint the generator synchronizing breakers trip open. The gensets are then put in the cooldown mode of operation.

This mode seeks to maintain constant utility contribution to a site load. This is accomplished by monitoring utility contribution and trimming generator set load levels up and down as site loads change. Import control means the generator set is contributing less than the total site load requirements, and the utility supplies the difference. Export control means the generator set is contributing more than the total site load requirements, and the utility is absorbing the difference.