Generac Power Systems CorePower 6/7 kW 60 Hz Diagnostic Repair Manual page 21

GENERAL INFORMATION
INTRODUCTION
When the generator is installed in conjunction with a transfer
switch, either manual or automatic operation is possible.
UTILITY FAILURE
Initial Conditions
The generator is in AUTO, ready to run, and the transfer switch is
in the Utility position. When Utility fails, a line interrupt delay timer
is started. If the Utility is still not present when the timer expires,
the engine will crank and start. Once started an engine warm-up
timer will start.
When the warm-up timer expires the controller will transfer load
to the generator. If Utility voltage is restored at any time between
the initiation of the engine start and when the generator is ready
to accept load, (warm-up time has not elapsed), the controller will
complete the start cycle and run the generator through its normal
cool down cycle; however the switch will remain in the "Utility"
position.
Utility Failure
(falls below percentage of
nominal)
Utility Restored
(returns above percentage of
nominal)
Line Interrupt Delay Time
CRANKING
CorePower
The controller will cyclic crank the engine 5 times as follows:
16 second crank, 7 second rest, 16 second crank, 7 second rest,
followed by 3 additional cycles of 7 second crank followed by 7
second rests.
PowerPact
The controller will cyclic crank the engine 5 times as follows:
16 second crank, 7 second pause, 16 second crank, 7 second
pause, followed by 3 additional cycles of 7 second cranks and 3
second rests.
Failure To Start
Failure to start is defined as any of the following occurrences
during cranking.
1. Not reaching starter dropout within the specified crank cycle.
Note: Starter dropout is defined as 4 cycles at 1,000 RPM
2. Reaching starter dropout, but not reaching 2200 rpm within
15 seconds. After which the controller will go into a rest
cycle of 7 seconds, then continue the rest of the crank cycle.
PART 1
CorePower PowerPact
65% 65%
75% 80%
5 seconds 60 Hz)
10 seconds
30 seconds (50 Hz)
Automatic Operating Parameters
3. If the unit does not start during the crank sequence, the
control panel Overcrank Alarm LED will illuminate.
Note: During a rest cycle the start and fuel outputs are de-
energized and the magneto output is shorted to ground.
CRANKING CONDITIONS
The following notes apply during the crank cycle
1. Starter motor will not engage within 5 seconds of the engine
shutting down.
2. The fuel output will not be energized with the starter
3. The starter and magneto outputs will be energized together.
4. Once the starter energizes, the controller will begin looking
for engine rotation. If it does not see an RPM signal within
3 seconds it will shut down and latch out on "RPM Sensor
loss"
5. Once the controller sees an RPM signal it will energize the
fuel solenoid and continue the crank sequence. The fuel
solenoid does not activate earlier because if the engine
does not crank, this would potentially fill the engine/exhaust
up with unspent fuel. It takes at least 3 seconds to detect
cranking on the engine with a magneto RPM measurement.
This would result in 3 seconds of fuel being delivered,
increasing the chances of a backfire.
6. The starter motor will disengage when speed reaches starter
dropout.
7. If the unit does not start during the initial crank sequence, or
if the generator does not reach 2200 rpm within 15 seconds,
a re-crank cycle will occur, which may result in up to 6 crank
attempts total.
8. If the engine stops turning between starter dropout and 2200
RPM the controller will go into a rest cycle of 7 seconds and
re-crank ( if additional crank cycles exist.)
9. Once started the generator will wait for a hold off period
before starting to monitor oil temperature and either oil
pressure (CorePower) or oil level (PowerPact). Refer to
Section 4.2 "Engine Protective Devices"
10. During a MANUAL crank attempt, if the controller is switched
from MANUAL to OFF, the crank attempt will abort.
11. During automatic crank attempt, if the Utility returns, the
crank cycle does NOT abort, but continues until complete.
Once the engine starts, it will run for one minute then
shutdown.
Section 1.5
Page 19