Download Emergency Diesel Generator Preventive Maintenance PDF

TitleEmergency Diesel Generator Preventive Maintenance
TagsTurbocharger Diesel Engine Fuel Injection Piston Cylinder (Engine)
File Size426.2 KB
Total Pages28
Table of Contents
                            LESSON 1 ENABLING OBJECTIVES
	CORRECTIVE ACTIONS
		CAUSE
	BROKEN ROCKER ARM DAMAGES TURBOCHARGER
Recent Industry Events
	ZION STATION CYLINDER LINER FAILURE
	WATERFORD CRANKCASE OVERPRESSURIZATION (EXPLOSION) EVENT
		Event Description
			CAUSE
			CORRECTIVE ACTIONS
		CRDR 2562611 Unit I “B” Diesel Governor Failure
			CHECK AIR START TIMING
			ADJUST TAPPETS
			FOUNDATION FASTENER TORQUE CHECK
			MEASURE MAIN BEARING CLEARANCE
			MEASURE CONNECTING ROD BEARING CLEARANCE
			PERFORM CAM/AUXILIARY DRIVE INSPECTIONS
			CLEAN AND INSPECT THE TURBOCHARGER
				Cause:  Electrical engineer inspected the DG OST Butterfly and suspects the increased air flow from the increased load resulted in the valve leaving its limit switch; thereby giving the indications of an overspeed trip.
                        
Document Text Contents
Page 1

Emergency Diesel Generator

Preventive Maintenance

Page 14

14

CRDR 2562611 Unit I “B” Diesel Governor Failure

During U1R10, the speed-regulating governor on the 1B EDG was replaced with a
governor that had been refurbished by Engine Systems Incorporated (ESI).

Following replacement, the EDG was started in the test mode via 40OP-9DG02. The
diesel achieved rated voltage and frequency. The governor was vented and verified to have a
full range of control. The EDG was shutdown after running for approximately one hour. The
EDG second start was performed with the engine in the emergency mode. The EDG achieved
rated voltage and frequency, ran unloaded for approximately 30 minutes and then was shutdown.

A third start was performed with the electrical control power breakers open (no power to
the governor) and the EDG in the emergency mode. The EDG started and achieved rated voltage
and frequency solely on the mechanical governor. The EDG was shutdown after approximately
30 minutes run time. EDG was started in emergency mode for the 24-hour run. The EDG
achieved and stabilized at rated voltage and frequency. Approximately 35 seconds later, the
EDG speed ramped from 600 to 700 rpm over a 1.5 second span and the engine tripped on
overspeed.

The cumulative run time on the new governor was 2 hours. The failed governor was
transported to ESI for failure mode investigation. The investigation was witnessed by Palo
Verde engineering personnel.

When installed on the diesel generator, the governor is coupled to the engine via a
beveled drive/pinion gear arrangement. This arrangement provides a rotational speed input to
the governor. At ESI, the governor was placed upon a test stand, which simulates engine
rotational input to the governor. The governor did not respond to any speed inputs. While
providing a speed input, the governor cover was removed and it was noted that the flyweights
were not rotating.

Further testing of the governor was suspended and governor disassembly commenced.
Disassembly revealed that the flyweight drive shaft had sheared. Disassembly also found that
the idler gear had seized within the sub-governor base.
The most probable cause of the governor failure was the presence of a foreign material,
which passed between the idler gear and the sub-governor base. This caused the idler to seize
and resulted in shearing of the drive shaft.

Page 15

15

TERMINAL OBJECTIVE:

At the completion of the instruction, the mechanic will, explain preventive maintenance on the
Emergency Diesel Generator as demonstrated by passing the end of course exam with a score of
80% or better.








LESSON 2 ENABLING OBJECTIVES

EO01 Explain the basic steps necessary to check Air Start System timing.

EO02 Explain the basic steps necessary to remove and check Fuel Nozzle lift pressure.

EO03 Explain the basic steps necessary to perform engine internal inspection.

EO04 Explain the basic steps necessary to inspect Rocker Arm Assemblies without disassembly.

EO05 Explain the basic steps necessary to adjust Main Valve Tappets.

EO06 Explain the basic steps necessary to check Foundation Fastener torque.

EO07 Explain the basic steps necessary to measure Main Bearing Clearance.

EOO8 Explain the basic steps necessary to measure Connecting Rod Bearing clearances.

EO09 Explain the basic steps necessary to measure the main thrust bearing clearance.

EO10 Explain the basic steps necessary to check Camshaft timing.

EO11 Explain the basic steps necessary to perform Cam/Auxiliary Drive Inspections.

EO12 Explain the basic steps necessary to set up and to inspect the Turbocharger.

EO13 Explain the basic process of performing power cylinder maintenance.

Page 27

27

Install the piston ring entering funnel onto the liner. Lubricate the liner and piston with Rotella
T-40 oil. Slowly lower the piston and pin into the liner. Use caution not to chop or break the
piston rings.
Use cribbing or other suitable means to center the rod in the liner. Ensure the piston pin is
seated properly in the saddle. Remove the piston pin alignment pins and install the pin bolts and
washers into the pin in their original location. Lubricate using Lubriplate # 630.
Clean, inspect and lubricate the articulating rod pin bolts with Lubriplate # 630. Torque the
articulating rod bolts. This torque is considerably higher than the piston pin bolt torque value. It
is extremely important to apply proper torque to drive train fasteners on the diesel engine as
insufficient torque could result in fatigue failure of the fasteners.

Head reinstallation instructions
Verify the torque of the head studs to be 975 ft-lbs. Install new O-rings onto the upper two
grooves on the liner jumper tubes. Lubricate the jumper tube O-rings with Lubriplate #630.
Check/verify the crosshead to crosshead guide to be 0.004” to 0.007”. (Ref drawing M018-
00619, Note 1) Install shims onto the head around both of the crosshead guides.
Lubricate new O-rings with Lubriplate #630 and install them onto the head around both of the
crosshead guides.
Lubricate new quad ring with Lubriplate #630 and install a new quad ring onto the oil return
tube on the head.
Install a new air start header gasket.
Attach the head lift rig to the head and tighten the fasteners using good mechanical judgement.
Lubricate the crossheads with Rotella T-40. Install the crosshead into the head and secure them
with the “hair pins”.
Coat around the base of each head stud with Right Stuff
Install a new fire gasket onto the liner.
Carefully install the head onto the engine ensuring that fuel leak-off and oil drain lines make-up
properly as the head is set in place. Using a borescope, ensure the fire gasket is not hanging over
the liner into the combustion chamber.
Check the crosshead guides to ensure there is no place around the crosshead to engine that a zero
clearance is present.
Clean and inspect the threads on the studs. Clean and inspect the flat washers for cracks or
defects. Lubricate the studs, nuts and washers with DOW Corning GN paste. Install the washers
and nuts onto the studs. Torque the head bolts in approximately four equal steps to 1450 ft-lbs.
Check the crosshead guides to ensure there is no place around the crosshead to engine that a zero
clearance is present.
Clean and lubricate the air start header bolts with Lubriplate #630. Torque the air start header
bolts to 50 ft-lbs. Check the torque of the adjacent air start header bolts to 50 ft-lbs.
Clean and lubricate the exhaust header bolts with Neverseeze N-5000. Install a new exhaust
header gasket. Torque the header fasteners to 95 ft-lbs.

Clean and lubricate the jacket water return header bolts with Lubriplate #630. Install a new
jacket water return header gasket. Torque the jacket water return header fasteners to 50 ft-lbs.
Install a new intake header gasket (Gylon). Torque the intake header fasteners to 85 ft-lbs.
Clean and lubricate the fuel rack bracket bolts with Lubriplate #630. Install the fuel rack bracket
onto the head using the dowel pins. Torque the fuel rack bracket fasteners to 132 in-lbs.

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