Diesel Generator

Question 1

How much fuel is required to be onsite for the Diesel generators?

Answer 1

Enough fuel to provide onsite power for 7 days

Question 2

What happens to DG if electronic governor fails?

Answer 2

Fuel racks get positioned to max, DG speeds up, then the mechanical governor picks up and limits speed

Question 3

DG fuel transfer system What pump and LCV’s will be open/on @ 10” and going down on U-1?

Answer 3

Primary (0-1) and LCV’s open

• primary pump and LCV’s on @ 10.25”
• backup pump and LCV’s on @ 9.5”
• backup pump and LCV’s off @ 13.5”
• primary pump and LCV’s off @ 13.5”

U-1 pri 0-1, b/u 0-2 U-2 pri 0-2, b/u 0-1

Question 4

How many sources of excitation are there for the DG ?

What are they?

When are they in service?

Answer 4

Two Field flash

• vital 125 vdc
  
  • initial start (10 psig jacket water or 140 rpm)
• Self excitation (current xfmr output of DG)
  
  • after running (90% rated voltage)

Question 5

What are all the automatic trips of the S/D relay (DG)?

Answer 5

L- low lube oil Press (<40 psig)

E- emergency trip PB

G- diesel generator diff relay

O- overspeed, mechanical (1050 rpm)

* high jacket water temp 195 deg

* diesel overcrank (>10 sec)

Question 6

If a DG loses control power (control power fuse blows) how can you shut down the DG?

Answer 6

Manually trip the “mechanical overspeed trip lever”

Question 7

State two ways the DG is kept warm to ease starting

Answer 7

jacket water is kept warm - engine coolant is heated by electric heater (maintains 90-120, de-energized by DG start relay)

Lube oil is recirculated and heated - precirc pump circulates small amount of lube oil from reservoir (starts on jacket water press < 10 psig, stops > 10)

Lube oil elect heater - the recirc flow goes thru heater (energizes, jacket water press < 10 psig and l.o. flow)

Question 8

What are the auto starts to the DG’s?

Answer 8

• SI
• 4 kv S/U feeder UV
• 4 kv bus UV 1^st level
• 4 kv bus UV 2^nd level

Question 9

What signals open and close the DG air start solenoid valves?

Answer 9

Open:

• DG start signal

Close all four:

• Jacket water press > 10 psig
• RPM > 140
• overcrank (10 sec)

Close two: (backup signals)

• RPM > 800
• turbo assist timer times out (3 sec)

Question 10

Describe fire protection features of DG’s

Answer 10

Cardox system that can actuate by temp sensors or mech T-handle

• east roll up door closes (norm closed)
• west roll up doors (2) close (norm open)

Fuesable linke at 268 ºF, the fuel oil is isolated from DG

Question 11

What does the (DG) radiator cool?

Include cascading loads

Answer 11

Jacket water (which cools)

• cylinder heads
• cylinder block
• turbo
• turbo after cooler
• lube oil cooler

air cooling radiator comes from (70% outside/ 30% DG room)

• DG room (via circulation)

Question 12

What happens on DG start at:

Jacket water Press > 10 psig

RPM > 140

Answer 12

Jacket water Press

• starting solenoid valves close (if not already)
• crankcase exhausters start
• precirc pump stops
• electric L.O. heater stops
• Field is flashed (if not already)

RPM

• fuel oil priming tank isolated
• starting air solenoid valves close (if not already)
• DG field un-shorted
• Field is flashed (if not already)