Precourse ILT DG Flashcards
What will auto start a DG?
UV or SI
How long does the DG have to be loaded on a bus?
10 seconds
What will trip a DG regardless of how it started?
Overspeed (660 rpm)
Generator differential current
Emergency Stop Pushbutton
What are the pressure trips on a DG in test mode?
Low lube oil pressure 30 psig
Low turbocharger oil pressure 30 psig
High crankcase pressure 0.5 psig
What is the design bases for the DG?
Loaded onto the bus in 10 seconds
7 days of fuel
If blackout in one unit, other unit DG can provide safe shutdown power for 4 hours
When do Fuel Oil XFR pumps starts?
Both start when DG >280 rpm
One starts when low tank level 14” above centerline
What will trip DG output breaker on UV start?
F Loss of field U Underfrequency R Reverse Power N neutral overcurrent D Gen Diff current Overcurrent relay S SAT feed BRKR lockout E Stop PB
What will trip the DG output breaker on an SI start?
Differential current
Manual
After a DG start when does the CV pump sequence on?
0 seconds
Where are the DG sequencers powered from?
SARA DC 111
SARB DC 112
A sequencer timer AC 111
B sequencer timer AC 114
What are the DG ratings?
Continuous 5500 KW 954A
2000 hours 5935KW 1030A
2/24 6050KW 1050A
What is the difference between droop and isochronous mode on DG?
In iso mode governor maintains speed constant regardless of load
In droop speed lowers as load rises
After a DG start when does the SI pump sequence on?
5 seconds assuming there was an SI signal
After a DG start, when does the RH pump start?
10 seconds assuming there was a SI signal
After a DG start, when does the VC chiller sequence on?
15 seconds
After a DG start when does the CC pump sequence on?
20 seconds
After a DG start when does the SX pump and SX aux lube oil pump sequence on?
25 seconds
After a DG start when does the A AF pump sequence on?
35 seconds
After a DG start, when does the CS pump sequence on?
If there is a CS signal, 15-18 seconds then maintained at 40 seconds
If the DG starts due to an ESF bus undervoltage, what mode will it start in? Will speed and voltage control be available to the operator?
During a UV it will start in Emergency Mode, speed and voltage will not be available since in isochronous mode
If the DG is running and a loss of air occurs, what is the effect on the DG?
The only automatic trip available will be the overspeed trip
When does the DG pre-lube pump start?
When DG is shutdown and speed <280 rpm, oil heaters cycle on at 120F
When does the DG jacket water circulating pump start?
Pump and heaters cycle on/off when <280 rpm to maintain JW temp 120-130F
What are the temperature trips on a DG in test mode?
Jacket water temp high 205F
Main bearing high temp 228F
Generator bearing high temp 228F
connecting rod bearing temp 197F
What are the misc trips on a DG in test mode?
Engine overspeed 660rpm
EPB
Incomplete start sequence <280rpm @ 25+ seconds
Turbo charger thrust bearing failure 0.011in
SI signal
What are the electrical trips on a DG in test mode?
FURNODS
loss of Field Underfrequency Reverse power Neutral ground overcurrent Overcurrent Differential current SAT breaker 1412 lockout
List the interlocks necessary to manually close the DG output breaker
DG at rated speed and voltage No lockouts on 1412 1413 1414 Syncscope on Sync check satisfied (if bus energized) C/S to close
List the interlocks to auto close DG output breaker
DG at rated speed and voltage No lockouts on 1412 1413 1414 UV on bus 2/2 1411 1412 1414 open C/S in AT
