Operation
Integrated Load Center Owner’s Manual 15
Sequence of Operation
When acceptable utility source voltage is available,
observe the following sequences.
Sequence 1 - Voltage/Frequency Dropout
Utility source voltage/frequency drops below the utility
fail-low voltage/frequency or is above utility fail-high
voltage/frequency set point.
Sequence 2 - Line Interrupt Delay
•
Utility source voltage is above or below utility fail
range setting.
•Line interrupt delay is initiated by the voltage or
frequency out of range condition.
•If utility source remains out of range longer than the
delay setting, circuit board action closes the
automatic start circuit (wires 178 and 183). When
that circuit closes, the engine cranks and starts as
controlled by a circuit board in the generator’s
control panel.
•Once the standby generator starts and produces
voltage, go to sequence 3.
Sequence 3 - Engine Minimum Run and Warmup
Timers
•
The minimum run timer establishes the minimum
length of time for the generator to run before it can
be shut down. The timer prevents shutdown of a
cold engine. The timer is adjustable from 5–30
minutes; factory setting is 5 minutes.
•An engine warmup timer is also turned on. This
timer permits the engine to stabilize and warm up
before loads are transferred to standby. This timer
is adjustable from 0 seconds to 3 minutes. Factory
setting is 5 seconds.
Sequence 4 - Standby Voltage and Frequency
Sensors
If generator AC output voltage and frequency are above
the voltage and frequency set points, loads transfer to the
generator power source.
Sequence 5 - Voltage Pickup
If the utility voltage is restored in the range between the
utility pickup-low voltage and high voltage values with
hysteresis, sequence 6 will begin.
Sequence 6 - Return to Utility Timer
•
This timer prevents transfer that a utility source
voltage surge or transient might cause.
•Adjust timer between 1–30 minutes. Factory setting
is 1 minute.
•If utility voltage remains within the range from
sequence 5 for the time interval of the return to
utility timer setting, loads are transferred back to
the utility source.
Sequence 7 - Engine Cool Down Timer
•
The engine cool down timer starts after the switch
transfers loads back to utility. When the interval
has “timed out”, the automatic start circuit (wires
178 and 183) is opened, and the engine shuts
down.
•The timer permits the engine to run at no load for a
fixed time, so the engine internal temperature can
stabilize before shutting down.
•The timer can be set anywhere between 1–30
minutes. Factory setting is about 5 minutes.
NOTE: Actual time between transfer to utility and engine
shutdown is whichever is longer—the engine cool down
timer setting or any time remaining on engine minimum
run timer.
After the switch automatically transfers loads back to the
utility power source and the generator has shut down, the
system is “ready” for sequence 1 again.
To Next Page
Loading...
Need help?
General
