GAS TURBINEPetronas Gas BerhadGPP 5&618 December 2005

History of Gas TurbineGas turbine cycle is also known as Brayton Cycle Geoge Brayton 1870.The first gas turbine was constructed by Brown Boveri having a capacity of 4MW been installed at Neuchatel, Switzerland at efficiency of 17%.

GAS-TURBINE THEORYA simple gas turbine is comprised of three main sections a compressor, a combustor, and a turbine. The gas-turbine operates on the principle of the Brayton cycle, where compressed air is mixed with fuel, and burned under constant pressure conditions. The resulting hot gas is allowed to expand through a turbine to perform work. approximately two / thirds of this work is spent compressing the air, the rest is available for other work ie.( mechanical drive, electrical generation)

Brayton Cycle

Types of Gas TurbinesThere are two basic types of gas turbinesAero derivative units are aircraft jet engines modified to drive electrical generators Industrial gas turbines units robust construction, are suitable for base load operation

Aero derivative (from jet engine)

Industrial Gas Turbines

Gas Turbine with RegenerationOne variation of this basic cycle is the addition of a regenerator. A gas-turbine with a regenerator (heat exchanger) recaptures some of the energy in the exhaust gas, pre-heating the air entering the combustor. This cycle is typically used on low pressure ratio turbines.

Gas Turbine with Regeneration

HORSE POWERA unit of power equals to 33,000 ft-lb/min or 550 ft-lb/sec or 2,545 Btu/hr. 1hp = 746 watts

COMPRESSOR SURGEPulsating of compressor discharge pressure due to chokage as a result of too much of air to be handled

Blow Off Valve

Prevention against compressor surge during start up/ shut down and acceleration (The valve reduce back pressure by venting air to atm through BOV line to exhaust duct) and compressor began surging when front stages of compressor would be highly loaded(mid Span)

Type of Gas TurbineThere are two type of gas turbineSingle ShaftSplit Shaft

Single Shaft Gas Turbine

Single Shaft Gas TurbineThe single shaft gas turbine was develop primarily for the electric power industry and uses a compressor and a power turbine integrated on a common shaft. As the unit is used continuously at single rotational speed.

Split Shaft Gas TurbineInlet AirCombustion ChamberPower TurbineCompressorFuelHigh Power Turbine

Split Shaft Gas TurbineThe split shaft gas turbine was develop primarily for mechanical drive application like pump and compressor, where the output power and speed might be expected to be variable.

Main componentGas Generator (GG) which consist ofCompressor / air compressorCombustion chamberHigh Power Turbine (HPT)3. Power Turbine (PT)Casing for compressor and turbineAccessory (L.O, Sealing & etc)

Main component

Gas GeneratorThe gas generator consists of an axial flow compressor, combustion chambers and two-stage turbine.When in operation, air enters the gas generator inlet, passes through the inlet duct and enters the compressor, where the air is compressed to an approximate ratio of 18/1

The angles of the inlet guide vanes and first six stages of compressor vanes are varied as a function of gas generator speed and compressor inlet temperature.Changing the vane positions gives efficient operation of the compressor over a broad speed range, while maintaining an effective stall margin. The vane positions are controlled by a speed sensor and servo valve.

Air leaving the compressor, enters the combustion section. Here the temperature of some air is raised as a result of full combustion, which takes place inside the combustion liner. The remaining air entering the combustor section cools the combustion section,

Leaving the combustor, hot gas passes through the two-stage high pressure turbine, where energy is extracted from the gas to turn the axial compressor. Turbine blade and vane cooling air mixes with the mainstream gas it passes through the turbine.

Leaving the gas generator, the hot gas drives the free wheeling GT-61 power turbine. The power turbine provides the mechanical power output for the driven equipment.

CompressorThe compressor is driven by the turbine via a connecting shaft and has the job of drawing external air into the engine, pressurizing it, and passing it along to the combustion chamber.

Compressor

CompressorAxial compressor type is mostly used due to its high output and efficiency. (Usually variable blade could produce 16bar)Compressor design been improve byImproving blade profileImproving blade sealingImproving blade material to withstand high temperature.

1.Centrifugal compressorThis compressor uses a spinning impeller to draw in intake air and accelerates it outward by means of centrifugal force into a diffuser.It is used in small gas turbines and is best suited for low pressure ratios where the overall engine diameter is not important.

2.Axial flow compressor Consists of rotating blades and stationary vanes. Air is compressed as it flows axially along the shaft. This allows greater efficiency and higher pressure ratios by multi-stage construction. A stage of compression consists of one row of rotating blades followed by a row of stationary vanes. This is the most common type of compressor used in marine gas turbine engines.

Compressor component

Variable stator

Air flowAir for gas generator combustion flows through air inlet filter, silencer and plenum before entering the gas generator

Combustor sectionFunction :Provide proper mixing of fuel and air for efficient combustionCombustorfuel and air are mixed and combust.burner systemdisperse/atomize the fuel ignition systemignite the main flame

Fuel sprayed from the fuel injector nozzles, mixes with high-pressure air entering the combustion chamber through its perforations from the compressor.This mixture of compressed air and fuel then burns at temperatures approaching 2000oC , in order to maximize the heat energy obtained

The combustion process is first initiated by igniter plugs, which are then isolated after ignition has been accomplished.The combustion of the fuel and air mixture is continuous and remains so until the fuel supply is removed.

Zone in which fuel is evaporated and mixed with airZone in which fuel is ignitedAnd burnt Heat is generatedCooling air

combustorCombustion chamber configuration1.Single Silo compressor is mixed with fuel and ignited in this chamber3.Twin silo (each consist of multiple burners)4.Can annular (ez maintenance & better balance)5.Annular ring (popular for >200MW)

Silo combustorSilo combustion chamber in its simplest formconsist of single burner or multiple burner. Compressed air from theThe hot gas is then lead to the turbine section

Silo combustorDisadvantageinfluence the size of the turbine house.Advantagefurnace inspection can be done easily because of it big size.

Silo combustor

Can Annular combustorIndividual burner cans are mounted around the periphery of the engine. Each can is an individual combustor and liner receiving its own fuel supply. Advantage: Easy replacement Disadvantages - Inefficient, structurally weaker

Annular combustorOne large combustor within the engine case. Multiple fuel nozzles form a solid "ring of fire". This type is used on the LM2500Advantage Most efficient, strongest, frame member of engineDisadvantageA repair or replacement requires complete engine disassembly.

Annular combustor

High Power Turbine & Power TurbineFunction To convert high pressure and temperature combustion gases into mechanical energy and drive the compressor and generator.

turbine blades converts the kinetic energy into mechanical energy

High Power Turbine

HPT cooling

Cooling HPT

Power Turbine

GG lube oilSynthetic oil is used for the gas generator. The console is mounted outside of the turbine enclosure.

Hydraulic oil after filtration is routed to the fuel metering valve actuator. Hydraulic oil exiting the fuel metering valve actuator is returned to the reservoir.

Lube oil after filtration is routed to the accessory gearbox and bearing sumps. The lube oil is removed from the accessory gearbox and bearing sumps by scavenge pump P5-0502. The oil passes through filter S5-0506 which has a pressure 505-PTD-1171 set to alarm at 30 psig (207 kPa G) increasing on gauge 505-PDG-1171.

Magnetic chip detectors are installed in the drain lines from the accessory gearbox and each gas generator bearing sump ahead of the scavenging pumps. An additional magnetic chip detector is installed in the common drain header. Metal carried by the drain oil will accumulate on the detectors and signal an alarm.

Scavenge oil after filtration flows to Cooler E5-0502. A temperature valve 505-TCV-1173 regulates oil flow through or around the cooler to maintain oil temperature at 60C.

Air oil separator

GG lube oil sump

GG lube oil7bar36bar

Power Turbine and Compressor Lube Oil

Mineral oil is used for the power turbine and compressor lubrication. The console is mounted outside of the turbine enclosure. Two pumps are used for normal operation. One pump is driven by an electric motor and is used for start-up and standby. The remaining pump is driven from the power turbine accessory gearbox and supplies all of the lube oil to the power turbine and compressor once the unit is in operation.

Oil from the pumps flows to a separately mounted fin fan cooler, E5-0506. Temperature control valve 505-TCV-1108 regulates oil flow through or around the cooler to maintain oil temperature at 49C.

Lube oil from the power turbine and compressor bearings is returned to the reservoir.A third oil pump, P5-0510 (Post Pump) is included in the lube oil console to provide cooling oil to the power turbine after shutdown. Unit control panel logic will start pump P5-0510 after main unit shutdown has commenced.

Lube Oil System (PT)Emergency pump

Safety precautions

The following safety precautions must be observed when adding lubricant (top up):1. Avoid touching moving parts of the machine2. Keep loose clothing well away from moving parts 3. Avoid spilling lubricant onto hot surface 4. Clear up spillage immediately 5. Do not remove safety protection from the machine

A good quality of lube oil

Continuous check of physical oil characteristics during operation will predict warrant of machinery life spent, maintenance cost and time saving. The oil shall be oxidation, foam inhibited and have good demulsibility for rapid separation of water.

Lube oil filter S5-0510A/B hydraulic filters S5-0508A/Bscavenge oil filter S5-0506PDI alarm at 30 psig

Operating precautions

Avoid mixing different grades of oilAvoid mixing different grades of greaseAvoid mixing with water or other liquids Avoid contamination with dust or dirt Check that oil cans are free of all foreign materials before fillingAvoid overfilling equipment

Routine Checks

During the shift, routine checks must be carried out on a regular basis.The operator must carry out routine checks immediately upon taking over the shift to ascertain the operating conditions of the unit and/or equipment.Just prior to the end of the shift, the operator must again check the unit and/or equipment to ensure that his handover to the next operator is accurate and gives a true reflection of the situation at that time.Operating troubles that may have been experienced on the unit and/or equipment should be recorded in the log book and verbally

The following check shall be carried out.Check oil level.Check oil temperature Check oil pressureCheck and drain water.(Investigate reason for water in the bearing.).Take samples for laboratory analysis when requested

Fuel and Start Gas With control panel switches in proper position for a unit start, the logic circuits cause the following events to occur.

Once purge cycle is complete, upstream fuel gas valve (505-XCV-1181) is energised to open. Vent valve (505-XCV-1183) is energised closed and the igniters are switched on. Starting gas flow control valve (505-PCV-1192) is ramped fully open to bring starter up to high speed to crank the gas generator for startup.

Fuel gas block valve (505-XCV-1184) is energised open. Fuel is ignited in the combustion chambers of the gas generator and speed ramps up to idle.Once at idle the igniters are switched off. Starting gas flow control valve (505-PCV-1192) is de-energised closed. Starting gas upstream shutoff valve (505-XCV-1191 ) is de-energised closed and the starter is shutdown.

Enclosure ventilation systemThe enclosure surrounding the gas generator and power turbine is provided with a ventilation system.Air is pulled from the inlet air filter through a silencer by an electric driven fanThree fans are used for the ventilation system.Two fans are to be used during normal operation and the third fan is for emergency use.

The ventilation air passes through fire shutters before entering the enclosure.The shutter actuator is activated by the fire suppression system.

The differential pressure within the enclosure is monitored by a differential pressure switch 505-PDS-1207alarm and start the emergency ventilation fan at 2.54 mm H2O decreasingshutdown after 60 second delay if the differential pressure does not increase above the alarm setting

Fire and Gas Suppression Systems Gas detectors 505-AE-1211, 1212 and 1213 are located in the intake plenum. Gas detectors 505-AE-1214, 1215 and 1216 are located in the turbine enclosure The gas sensors monitor gas levels within the plenum and enclosure. An alarm is sounded if gas levels reach 20%. Shutdown occurs if gas levels reach 60%.

All access doors to the air filter enclosure, intake plenum and turbine enclosure are fitted with limit switches which will sound an alarm if any door is left open.Fire detectors are placed in the turbine enclosure. The fire detectors are of the optical type, and response to ultraviolet and infrared radiation which is emitted by flame. The detectors have a 120 field of view.

When the detector senses UV or IR radiation, it signals the control panel module. The module issues signals to trigger release of CO2, and closes the fire damper doors to isolate the fire in the enclosure. Two dump nozzles 559 and 560 are provided. The 559 nozzles dump the CO2 into the enclosure at a fast rate. The 560 nozzle dumps the CO2 at a slow rate. The CO2 bottles are stored in a cabinet which is adjacent to the unit. Two CO2 tanks are provided for the main system (fast dump) and one CO2 tank is provided for the extended system (slow dump). A duplicate set of reserve tanks are also included in the system.

WARNINGPERSONNEL SHOULD NOT BE EXPOSED TO HIGH CONCENTRATIONS OF FOR PROLONGED PERIODS TO CO2 DISCHARGE. CO2 MAY CAUSE SUFFOCATION AND REDUCED VISIBILITY DURING AND AFTER A DISCHARGE PERIOD.

Gas Detector Fire Detector (Optical)Fast DischargeSlow DischargeAlarm 20%S/Down 60%Response to ultraviolet and infraredGas Turbine EnclosureCO2CO2TemperatureAlarm 71deg CS/down 80deg C

Periodic MaintenanceEvery 4000 Running hours detergent wash with boroscope

25,000 Running hours Replacement of the Hot SectionNote; Depend on vender recommendation

Water wash system

Purpose: Used to remove dirt and salt buildup on the compressor blades. Components: Consists of a 40 gallon tank and permanently installed piping to direct water wash solution into the inlet of the compressor. Procedure: Compressor must be washed to maintain efficiency and prevent compressor stalls.

EXHAUST SYSTEMFunction:- Convey hot exhaust gases to either atmosphere or waste heat boiler

exhaust casing - provides exhaust gases flow path

exhaust ducting and silencer- routes the exhaust gases to chimney or waste heat boiler with a reduction in noise

UNIT START-UP Types of start-up1. Start-up after maintenance.2. Start-up after temporary shut-down.3. Start-up after emergency shut-down.

Start-up after Maintenance SummaryFollowing a planned shutdown for maintenance and inspection, the equipment are handed back to operations department for start up.Pressure tests must be made to ensure that all disturbed flanges, valves and pipe work are leak free

2. The whole system must be thoroughly purged of air by using nitrogen 3. AII accessories and equipment related to the operation of the main equipment must be checked out correctly.4. Check that all the platforms and immediate external areas are clean and unwanted material removed.

Operating precautions

Fuel and Start SystemWARNINGINSTRUMENT BLOCK VALVES IN SENSING LINES TO PT-1182 (Fuel Gas), PS-1187 (Fuel Gas), PS-1193 (Start-up Gas), PG-1195 (Starter Exhaust) AND PGT-1190 (Instrument Air supply) MUST BE IN THE OPENED POSITION WHEN UNIT IS OPERATIONAL. UNIT OPERATION WITH BLOCK VALVES CLOSED COULD DISABLE THE SHUTDOWN SIGNAL FROM THE SWITCHES, WHICH MAY CAUSE EQUIPMENT DAMAGE AND OR PERSONNEL INJURY.

CAUTIONWATER WASH VALVE IS OPENED ONLY WHEN USING A WATER WASH CART.OPEN EXHAUST CASING DRAIN VALVE AFTER WATER WASH CART HAS BEEN USED TO CLEAN THE UNIT OR TO REMOVE LIQUID WHICH HAS ACCUMULATED DURING UNIT OPERATION.

Gas Generator Lube Oil SystemThe pressure and temperature checks can only be made after the gas generator is in operation.

Normal Start Sequence A Normal Start Sequence can only be initiated locally from the Local Control Panel (LCP). When the mode select switch on the LCP is in Local, a Normal Start is initiated by depressing the Start push button (PB-1314) on the face of the LCP.

"Permissive To Start."

Gas Generator Oil Reservoir Level is OK Power Turbine / Compressor Oil Reservoir Level is OKFuel Metering Valve is at Minimum Position (ZS-1186)Fuel Shutoff Valves are closedStart Gas Shutoff Vent Valves are closed (ZSC-1191)AC Power "OK" Vibration Monitor is "OK"Turbine Enclosure Doors are closedUnit Process Valves are in Shutdown (Prestart) Position

Gas Generator Coastdown Timer Time out Gas Generator Speed (N1) Ramp is at MinimumPower Turbine Speed (N2) Ramp is at MinimumLCP Run Local Mode is Selected (SS-1402)All Fire and Gas System Alarms are ClearedAll Trip to Idle/Recycle Alarms are ClearedUnit Shutdown is ClearedBuffer Gas Supply is greater than the Low AlarmFuel Control Summary Shutdown is Cleared

NOTEIf the Permissive To Start pilot light is not illuminated on the face of the LCP, select the Start Permissive Screen on the Operator Interface CRT the status for each of the above conditions will be displayed. The corrective action for each point should be taken in order to achieve a Unit Start Permissive.

Immediately after the Start push button is depressed The Turbine Enclosure Fan selected as Main will be startedThe PT Seal Air Supply valve is openedThe Compressor Separation (Buffer) Gas Supply valve is openedUpon establishing of the Compressor Seal Gas Separation Pressure, the PT Post Cooling Oil Pump is started for test purposesThe Standby Lube Oil Pump is started and a Standby Lube Oil Pump test is initiated

Auxiliary Sequences Stand-by Lube Oil Pump TestPower Turbine/Compressor Lube Oil PressureLube Oil Pump SequenceEnclosure fan SequenceSeal Gas System After the Auxiliary Sequence has been completed, the Purge and Pressurising Sequence for the Compressor will be initiate

Pressurising Sequence The Suction Bypass Valve (505-XV-0102) is opened.When the Differential Pressure across the Suction Valve (505-XV-0101) is reduced to less than 1.0 Bar the Suction Valve (505-XV-0101) will openAfter the Suction Valve is fully open, the Suction Bypass Valve (505-XV-0102) closes and the Discharge Valve (505-XV-0103) will open

Gas Turbine Start Sequence The Gas Starter Control and Shutoff Solenoids 505-XY-1192 and 505-XY-1191 are energisedThe Primary Fuel Gas Shutoff Solenoid (505-XY-1181) is energised to openThe Starter Speed Control Output will be ramped up until the Gas Generator Speed (N1) has achieved 1250 RPM

If the Gas Generator fails to reach 1200 RPM within thirty (30) seconds, a Fail To Crank Shutdown will be initiated; thus the Unit Start/Run Sequence will be aborted.GG Speed (N1) will be controlled between 1250 and 1350 RPM to purge the Plenum, GG, PT/Exhaust Duct and the GG Purge Timer (TM-08) will begin to time out.When the GG Purge Timer has timed out, the Starter Speed Control Card High Speed command will be enabled and the Starter Speed Control Output will ramp up to maximum.

The Gas Generator will begin to accelerate. and. The Ignitors (A or B) are alternated on successive starts of the Gas Generator.

The Fuel Gas Vent solenoid (XY-1183) will be energised to close.The Ignitor Relay (A or B) (IGN-1261 or 1262) is energisedThe Fuel Gas Secondary Shutoff Valve Solenoid (505-XY-1184) is energised to open 505-XV-1184

Light Off (T5.4 greater than 204C) must be verified within 10 seconds after the Secondary Shutoff is opened or a "Fail to Light Off Shutdown " is initiated. This will then initiate a High Speed Purge of the Gas Generator at greater than 2000 RPM to rid it of any residual fuel.

Once Light Off has been verified, the Gas Generator will continue to accelerate until the GG Speed (N1 ) has achieved 4500 RPM. When the GG Speed (N1 ) is greater than 4500 RPM, the Starter Control Signal is disabled and both the Gas Starter Supply and Shutoff Solenoids are de-energised. Simultaneously, the Ignition is also disabled. The Gas Generator continues accelerating to Idle.

Once the Gas Generator has reached Idle Speed (5000 RPM), the Unit Warmup Timer will begin to time out. When the warmup Timer has time out, the Unit is ready to load.When the Unit Load Sequence is initiated, the GG will accelerate until the Power Turbine minimum speed (3250 RPM) is achieved. The Unit will now be operated in Power Turbine Speed Control Mode.

Normal operation & routine checks

During the shift, routine checks must be carried out on a regular basis.The operator must carry out routine checks immediately upon taking over the shift to ascertain the operating conditions of the unit and/or equipment.Just prior to the end of the shift, the operator must again check the unit and/or equipment to ensure that his handover to the next operator is accurate and gives a true reflection of the situation at that time.

Operating troubles that may have been experienced on the unit and/or equipment should be recorded in the log book and verbally communicated to the incoming operator.

Operating aspects to be monitored in order to keep the performance of the unit under control and to identify proper corrective actions are:Compressor and Turbine vibrations Compressor and Turbine axial displacement Temperature and pressure of the lube oil systems. Differential pressure across the Lube Oil Filters. Differential pressure across the Hydraulic Oil Filters. Status of the Lube Oil Stand-by Pumps. Differential pressure across Seal Gas Filters. Differential pressure across Nitrogen Buffer Gas Filters. Differential pressure across Instrumental air Filters. Gas Generator speed. Power Turbine/Compressor speed.

Types of shut down

Shut down for maintenanceTemporary shut-down.Emergency shut-down.

Scheduled shut-down

Scheduled shut-downs occur at infrequent intervals and are carefully planned. This enables preventive maintenance work to be carried out e.g. internal inspection of an equipment.All maintenance work which cannot be handled whilst the Equipment is in operation is carried out at this time. A Previously prepared shut-down procedure and work list must be strictly adhered to. This will ensure a safe, controlled shut-down and a minimum loss of time in completing maintenance work.

Operating precautions

Close co-ordination between the Panel Operator and Field Operator is essential for good control. Safe operating procedures and safety regulations must be followed at all times.Coordinate with other Units and warn the other departments, especially the Fire Department.

Temporary shut down

A temporary shut-down is unscheduled and may only last for a few hours. The shut-down follows the same procedure as for a scheduled shut-down except that the pressure should be maintained ready for immediate start up.A temporary shut-down is usually due to operational requirements, or, a unit upset of short duration. Every effort must be made to return to normal operations as soon as possible.

Emergency shut-down

An emergency shut-down can be caused by equipment failures related to the plant operation or utility failures, e.g. loss of instrument air.In the event of an emergency shut-down being necessary the unit must be taken out of service as quickly and safely as possible.The prevailing conditions at the time must be taken into consideration when shutting down the unit.

WARNINGSafety of personnel and the prevention of damage to equipment are the primary considerations. All operations personnel must be thoroughly conversant with the procedures to be taken for an emergency shut-down.

The exact procedure to follow must be decided in the light of individual circumstances at the time. Frequent checking of equipment can normally give adequate warning of impending trouble and allow a normal shut-down to be effected.

A thorough knowledge of all the equipment related to unit operation is essential.The main causes of unit emergencies are: power failure, instrument air failure, fuel gas failure.

Unit Vented Shutdown Sequence

Unit Vented Shutdown requires depressurising the Compressor.When a Vented Shutdown is initiated, Fuel Gas is immediately cut off, the Turbine begins coasting to a stop and Compressor Vent Valve is opened.

The following conditions will initiate a Vented Shutdown:CO2 Release ShutdownCommon Fire ShutdownInlet Plenum Gas ShutdownTurbine Enclosure Gas ShutdownCompressor Vibrations ShutdownCompressor Thrust ShutdownGas Seal Vent Leakage Primary High Shutdown or Signal Fail

PT/Compressor Lube Oil Supply Pressure Low Shutdown or Signal FailCompressor Rupture Disc Failure ShutdownProcess Shutdown VentedUnit ESD2 of 3 CPUs Failure Shutdown

Engine troubleshootingTroubleshooting is a systematic analysis of symptoms that indicate equipment malfunction. These symptoms usually appear as deviations from normal values of observed equipment parameters.

Before concluding that an engine fault does exist, the troubleshooter must assure that his knowledge of suspected trouble area is adequate, that the instruments used are calibrated and working properly, and that they have been accurately read and interpreted.

NOTEIf troubleshooting procedures do not isolate and eliminate the fault, secure assistance from vendor service representative through your customer service manager.

GG Fails to reach maximum motoring speedIf engine is hot, allow it to cool for 30minutes and then attempt motoring.Check starter supply pressure. If pressure is below minimum limit, check pressure source.Check instrumentation. Replace indicator if defective.Replace starter.if the rotation is still low,perform borescope inspection of compressor and HPT. Check scavenge oil screens for sump problems.

GG Fails to Light OffCheck to make sure GG will motor to 2000-2500 rpm on the starter.Check supply pressure to fuel control and fuel manifoldIf fuel supply pressure are within the limits, troubleshoot ignition system.

CAUTIONALWAYS PURGE FUEL FROM GAS GENERATOR BY MOTORING THE GAS GENERATOR AFTER ANY FALSE START

WARNINGNO FUEL AIR MIXTURE MAY BE PRESENT DURING THIS TEST.HIGH VOLTAGE EXISTS AT THE IGNITERS, THEY MUST NOT BE TOUCHED WHILE ENERGIZED.

High Vibration in Gas GeneratorCheck that vibration instrument and its wiring are operating properlyCheck that vibration pickup is securely mounted.Inspect oil scavenge and magnetic plugs in lube scavenge pump.Water wash compressor if inspection reveals dirty blades and vanes.

High Vibration in Power TurbineCheck that vibration instrument and its wiring are operating properlyCheck that vibration pickup is securely mounted.Inspect oil scavenge and magnetic plugs in lube scavenge pump.

Low Lube Oil PressureOil pressure is a function of gas generator speed and supply temperature.If oil supply pressure is low,check supply oil filters for cleanliness and supply line for leaks. If low pressure persists, replace lube/scavenge pump.