Generator control system
Based on VCS183
DS_VCS183
Page 14
Rev. 06
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©Fischer Panda generators Inc.
Cumulative data
While the generator is running the control system will keep track of total operating time, operating time
since last start, total energy produced and energy produced since last start. These cumulative data along
with the total number of engine starts allow an estimation of average generator load and average
generator operating time between two starts. Whenever running without working CT186 energy is
logged to be zero.
Initiating generator stop
Any emergency shutdown will initiate a generator stop. If the stop was requested by the panel and the
VCS ha
s the “Cooldown” option enabled (P62) then it will transition to operating mode “cooldown”. The
control system will not enter cooling down mode if it detects the generator is loaded with 25% or more
of its nominal power. In such case it will assume the user requests an immediate stop and will skip
cooldown phase.
Cooling down
While in cooldown mode the control system will maintain all regulation and monitoring tasks unchanged
as compared to regular running mode. It will exit cooldown mode and transition to shutting down mode
if one of below conditions becomes true:
•
Cylinder head temperature drops to cooling down temp. threshold (P58) or below
•
Maximum cooling down time (P59) elapsed
•
The panel is sending another stop request. This will be interpreted as an immediate stop
demand, regardless of cooldown status.
Stopping the generator
Once generator stop is initiated monitoring is reduced to same criteria as in stop mode (
). If the auxiliary output is configured as ground breaker then the control system will first
turn on the ground breaker output
–
provided it is not marked permanently shorted to ground. After
giving it some time to activate the relay the control system will turn off power to the fuel pump and
activate the stop solenoid, if it is configured as energized to stop (P62). It will now keep the stop
solenoid output active for minimum 2 seconds and then for another 6 seconds or until engine speed
decayed below threshold, whichever comes first.
If engine speed does not decrease within maximum stop time (8sec) then the control system will turn
off power to the stop solenoid anyway. This is because obviously the stop solenoid is misaligned or
damaged and thus will not stop the engine anyway; it would be at risk of overheating if kept powered
for longer time. In
such case the operational status transfers to “cannot stop engine” and stop
procedure now will only occur because fuel supply gets cut-out by the fuel solenoid which works parallel
to the fuel pump.
After reading engine speed below run threshold the control system will change operational mode either
to “stop mode” if this was a regular engine stop (requested by the panel) or to “unacknowledged alarms
pending” if this was an emergency stop. No
t detecting speed signal for a certain time is reported as
“unexpected engine stop” but will also end up in operational mode “unacknowledged alarms pending”.
