There are hundreds of commercial crankcase oils marketed today. Obviously, engine manufacturers or users cannot completely evaluate the numerous commercial oils. The performance of a lubricant, ...
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Lube oil system 1.System component and function description 1.1 Lube oil tank Install at the base of accessory compartment to storage lube oil .Maximum capacity of lube oil tank is 1700 Gal.(6500 liter) . At the lube oil tank installed level switch 71QH-1 and 71QL-1 to alarm when lube oil tank level high or low to inform operator that lube oil in the lube oil storage tank is abnormal level. The cause of lube oil tank level low may be by large leak. When the levels switch 71QL-1 reach at low level “Lube oil level low alarm will be occur at mark V display. Operator should take care to see the level at level indicator at lube oil tank to verify lube oil level and verify system piping have leak or not .It is the good practice to add the lube oil to normal tank level(more than ½ tank) 71QH-1(L71QH) level switch for lube oil level high when the lube oil tank reach to High oil level the level switch will sent signal to mark V to alarm 109 “Lube oil level high . Operator should investigate the cause of alarm. The cause of alarm may be come from leakage of cooling water to lube oil system. See L71QH Seq _trb 1 68 L71QL Seq_trb 1 69
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26QL-1(Lube oil tank temperature on – off) When the lube oil temperature detected by 26 QL-1 decrease to 60 oF ( 15.5 oC ) contact of temperature switch must be close for connect heater circuit (23QT-1) and connect to lube oil pump 88QA to run for circulation of oil through heater (23QT-1)to heat lube oil temp increase until lube oil temp reach to 70 oF( 21 oC )contact 26QL-1 will open circuit of heater and stop 88QA 26QN-1(Lube oil tank temp normal )In the cold weather temperature below 50 oF ( 10 oC) that make lube oil temperature low (If 88QA not run and heater 23QT out of service alarm 111 “ lube oil tank temp low “will be occur to verify this alarm operator should read lube oil temperature indicator at lube oil tank . If this alarm still set mark V not permit to start turbine (not ready to start ) Note In hot country this alarm may not occur that may be temperature switch fault. See L26QN Seq _trb1 93 L3STSCK page 32 Seq_trb1 72 L26QN_ALM page 27
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1.2 Lube oil pump On the lube oil tank installed 3 pumps - Main lube oil pump driven by accessory gear - Auxiliary lube oil pump driven by AC. Motor - Emergency lube oil pump driven by DC. motor Lube oil pump sequence Normally 88QA will be the first priority to start lube oil system by command ‘on cool down‘’ or in sequence start up. In sequence of on cool down 88QA maintain pressure of lube oil to bearing and give suction pressure to Hydraulic ratchet pump. In sequence of start up 88QA will maintain the pressure of lube oil (88QA run) until speed of turbine reach 96.4% (4930rpm)and verify lube oil header pressure normal (more than 1.1 Bar within 2.5second)auxiliary lube oil pump will be stop and lube oil pressure maintained by main lube oil pump (Drive by accessory gear) During shut down cycle. If turbine have shutdown command after turbine speed decrease to 94.8%(L14HS drop out 4848 rpm)88 QA will be run until cool down off (turbine wheel space temp less than 65 oC and operator select ‘’ cool down off ‘ ) . Incase of turbine trip 88QA must be run when the signal L4 become to zero ‘0’ Incase of 88QA Still running when turbine speed more than 4848 rpm.(14HS pick up)and turbine not trip mark V will sent alarm 103 “’ Auxiliary lube oil pump motor running’’ operator must solve this problem before select to synchronize because if this problem not clear generator not permissive synchronize to system. See L4QAZ Seq_trb1 67 page 26 , L3X Seq_trb2 54.3page 69 L52QA_ALM Seq_trb1 65 page 25
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23QA (88QA motor space heater) the purpose of this heater is to protect the motor winding from moisture .The heater maintain winding warm when 88QA stop. After 88QA run this heater will be cut by auxiliary contact of 88QA
88QE Emergency lube oil pump DC. Motor drive lube oil pump. Function of 88QE is to pressurize lube oil system but 88QE use for the last priority when 88QA can not run See L4QEZ Seq _aux 62 page 25 Seq_trb1 63 page 25
VPR1Hydraulic trip pressure regulator valve (setting 3.45 bar) It use to regulate lube oil pressure before go to lube oil filter and lube oil cooler .After Lube oil go to header it will be regulated by VPR2-1(setting 1.72bar) The reason for VPR1 setting is to compensate pressure drop at piping and filter before go to header line. VPR 2 Lube oil header pressure regulator Regulate lube oil header after lube oil pass through lube oil filter to lube oil header line to maintain pressure at lube oil header =1.72 bar
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Lube oil cooler After lube oil cool the equipment and return lube oil tank temperature will increase .Thus system must have equipment to cool lube oil to proper temperature before go to equipment to protect equipment from temperature high such as bearing temperature high. Lube oil cooler use water from cooling water system for cooling lube oil . Temperature of lube oil regulated by VTR-1(set 49 oC) Lube oil filter The function is to protect lube oil header from impurity and solid particle. Two filter (5micron) installed before lube oil go to lube oil header to filtered impurity of oil or solid particle which contaminate oil act like abrasive upon the oil circuit part and the lubricated device .The filter should be change when the differential pressure gauge indicate a differential pressure of 1.035 bar -63QA-2 low lube oil pressure alarm (inc close 16±2 decrease open 12±1 psig) the function of this pressure switch is to monitor lube oil header if speed of turbine more than 14HS pick up normally 88QA pump should be stopped but if this pressure switch detect lube oil header pressure low than 0.8 bar and Alarm 107 will be Alarm “lube oil Pressure low“ See L63QT_SENSR Seq_Trb1 80 page 28 L63QT Seq_trb1 79 page 28 L63QAL_ALM Seq_trb1 70 page 26 L63QALY Seq_trb1 66 page 26
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-63QL low lube oil pressure emergency pump start (inc open 20±2 decrease close 6±1 psig) this function of pressure switch is to protect lube oil header pressure after turbine trip that mean 88QA fail to maintain pressure to continuous run turbine (if main oil pump fail also) to protect turbine shaft and bearing rub during coasting down -63QT2A and 63QT2B low lube oil header pressure trip (inc close 9±0.5 decrease open 8±0.3 psi) This low pressure switch (63QT2A,2B) for tripping turbine incase of lube oil header pressure low From Logic L63QT if we have 2 of 3 pressure switch 63QA-2 , L63QT2A,L63QT2B the turbine will be tripped by signal L63QT go to L63QTX and alarm 106 “LOW Lube oil pressure trip” at Mark V that mean main lube oil pump and auxiliary lube oil pump cannot maintain lube oil header pressure in the normal range (more than 0.8 psi) See L63QTSENSR Seq_trb1 80 page 28 L63QT Seq_trb1 79 page 28
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-26QA-1 (lube oil header high temp alarm setting 165°F (74°C) ) in this case the cause of problem may come from cooling water temp high or VTR1 cannot maintain lube oil temp When lube oil header increase to 74°C and the speed turbine more than 920 rpm Alarm 112 “Lube oil header temperature high “will be show at Mark V operator must take care to verify the problem and solve this problem before lube oil header increase to 79°C that will make turbine trip See L26QA Seq _Aux 13 L4FC1XX page 198 Seq_trb1 77 L26QT page 27 Seq_trb1 73 L26QA_ALM page 27
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-26QT-1A, 26QT-1B (lube oil header temp high trip inc open 175±3°F or 80±1.6°C) this two temperature switch use to verify lube oil header temp after lube oil header temp high Alarm (74°C) if any one of two or both temperature switch (26QT-1A, 26QT-1B) detect that lube oil header temperature over the setting it will trip the turbine and Alarm 113 Lube oil header temperature high trip See Seq_trb1 78 L26QT_SENSR page 28 Seq_trb1 77 L26QT page 27
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- Lube oil temperature thermocouple At lube oil header thermocouple has installed at the pipeline of lube oil header to detect temperature and sent to Mark V Operator can know the temperature of lube oil header temp by signal LTTH1 if this value (LTTH1) more than 74°C Mark V will Alarm 222 “bearing drain temperature high” and if LTTH more than 80°C turbine trip and Alarm No 407 Lube oil drain temperature high trip - Lube oil bearing drain temp LT-BT1D-1A, 1B Lube oil thermocouple #1 thrust drain LT-B1D-1A, 1B Lube oil thermocouple#1 bearing drain LT-B2D-1A, 1B Lube oil thermocouple #2 bearing drain LT-RG1D Lube oil thermocouple red gear comb brg. drain LT-G2D Lube oil thermocouple gen#2 brg. drain These thermocouple are used to detect lube oil drain temperature at bearing drain to show the value at Mark V and give alarm when bearing temperature more than 100°C (Alarm 222 bearing drain temperature high ) and trip turbine when bearing drain temperature more than 110°C and Alarm 407 lube oil drain temp high trip at Mark V Alarm See Rung Display Page 218 L30LOA , 219 L30LOT
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Lube oil mist eliminator Purpose The purpose of oil mist eliminator is • to extract the oil mist flow from the GT. lube oil tank • to create and adjust depression in GT. oil tank (Approximately 0.8 kPa) • and mainly .to eliminate oil droplets from the discharge air Starting up The blower of this unit will be start up automatically by speedtronic when auxiliary lube oil pump start or the speed of GT. reach 18% (14HM pick up ) of nominal speed provide that no GT. fire has been detected . and the switch on LV. Distribution panel (Q29) set auto Shutting down The blower motor is shutting down automatically by Speedtronic mark V after GT. speed fall below 15% (765 rpm.) of nominal speed & auxiliary pump stop. that mean in the cycle of cool down time 88QV still running until operator select cool down off . This commends go to stop 88QA and after 88QA stop 10 minute 88 QV will be stop. See L4QVZ1A Seq_aux 9 page 197 L4QVZ Seq_AUX 70 page 215 L94X Seq_trb1 55.2 page 21
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Precaution It is the most important for maintain 88 QV running when turbine running .If it is interrupted by stopping 88QV. The turbine will be shutdown by signal L94AX “Automatic shutdown’’ Alarm Incase of starting up Turbine If operator forget to on breaker of 88QV (Q29) when speed of turbine reach 18% of nominal speed (with delay time 3second) Mark V will be alarm No.405 ‘oil demister fan trouble .If the trouble doesn’t exist When speed reach to 94.6 %( 4930rpm.)Turbine will be shut down by automatic shut down. See L51QV_ALM Seq_AUX 69 page 215 L4QVZ Seq_AUX 70 page 215
Filter Coalescing diff pressure The purpose of coalescing filter is reducing oil loss from vapor system. Pre-filter and coalescing filter was installed at inlet of lube oil mist eliminator pump. Prefilter catch any solid particle ,Whilst at the same time allowing large oil drop to form .The largest drops are stop and are collected in the bottom of the inlet box. The oil then return to the GT. oil tank via the oil buffer box. The oil mist then pass through the filter element (demisting cartridge )which separate the very fine oil drop still percent in the air. If the coalescing filter diff pressure reach 12 kPa. Alarm No.404 “Oil Demister filter diff pressure high ‘’ will be occurred
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It is good practice for operator to take care this system by recording unit suction pressure (normally should be 0.5-0.8 kpa) and coalescing filter diff pressure must not over 12 kPa. By reading PDI 152 .If it is not in the recommended range should inform authorized person. See L63QV_ALM Seq_AUX 68 page 215
Start Up Lube oil system System flow must be prepare • 88 QA , 88QE breaker must be closed and put in auto • Lube oil cooler must be vented the air until assure no air in the cooler • Lube oil cooler must be vent the oil until assure that the oil full in the cooler by observed oil vent sight glass. If the oil Full in the cooler ,close filling valve • Assure that cooling water valve must be opened match with the cooler that selected to used. • Assure that lube oil filter filled with oil until full with oil • Verify all pressure gauge shut off valve are opened. If the system preparing finish ,When Mark V have command ‘’ On Cool down ‘’ or ‘’Start (crank, fire ,auto)” 88QA will be start automatically. Incase of auto start ,when speed of turbine reach to 4930 rpm.(14HS pickup) and system control verify that lube oil pressure normal 88QA will be stop Automatically but 88QV still running See L4QAZ Seq_trb 1 67 page 26 L4QVZ1A Seq_AUX 9 page 197 Lube oil system shut down During shut down cycle 88QA will be running when speed of turbine decrease to 4848rpm.(14HS drop out) . The pump will be running during on cool down period Until wheel space temperature less than 65oC and operator command to mark V to stop on cool down the turbine
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Special requirement and precaution *Lube oil level Operator must take care level of lube oil tank .If alarm lube oil level low occur ,Lube oil must add to lube oil tank to normal level *If Alarm lube oil temperature high, operator must solved the problems before lube oil temperature reach to 80 oC . The cause of lube oil temperature may be come from • 88FC 1-4 Not manual run • Lube oil cooler isolation valve of cooling water system not match with the selected lube oil cooler • Bearing header temperature regulating valve malfunction • Air block in lube oil cooler or lube oil filter Periodic test and check *L63QA -2 should be test in proper set period to verify that auxiliary lube oil pump can start when lube oil header pressure lower than setting (0.83bar) * L63QL should be test in proper set period to verify that DC. Lube oil pump can start when lube oil header pressure lower than setting (0.42bar) *For normal operation operator should monitor Lube oil header pressure, lube oil temperature at lease every 2hours * Lube oil filter must be changed when lube oil filter diff pressure over 1.2 bar
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Lube Oil System Test Name……………………………Shift……………Date………………. 1. From Logic L4QAZ when 88 QA start and stop ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… 2.When GT. speed reach to 5100 rpm.If 88QA still running .and you want to synchronize the generator .Can you synchronize the Generator to grid ? And tell me what the reason ? ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… 3.When 88QE start ? ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………… 4.If we have alarm 420 ‘’Over load emergency lube oil pump” Tell me the cause of alarm ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………….
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5.If Mark V have alarm 108 ‘’Lube oil pressure switch trouble ‘’ and gas turbine still running .If this alarm not clear when lube oil header pressure = 10 psig. Tell me can GT. running? And tell me the reason why? ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ……………………………… 6. When turbine go to 920 rpm. (14HM. Pickup) you see alarm lube oil header temp high at mark V. How can solve this problem? ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………… 7. When Lube oil header temp at Mark V show 74 oC what alarm will be occur. Follow the condition 7.1. When speed more than 14HM pick up this alarm will be occurred 7.1.1…………………………………………………………………………… 7.1.2…………………………………………………………………………… 7.2 When speed less than 14HM pick up this alarm will be occurred 7.2.1…………………………………………………………………………… 8.If lube oil temperature = 60 oF Can GT. start ? ( Yes or No ) ………………………………………………………………………………… 9.When 88 QV stop GT. will automatic shut down True or False ?. …………………………………………………………………………….. 10.Lube oil Mist eliminator suction pressure should be 0.5 - 0.8 Kpa. True or False? …………………………………………………………………………
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11.When lube oil mist eliminator coalescing filter differential pressure more than 12 Kpa. Alarm 405 Oil demister fan trouble will show at mark V True or False? ……………………………………………………………………………… 12. Ten minute after 88QA stop (and 14 HM drop out) Lube oil mist eliminator will be stopped True or False?. ………………………………………………………………………………. 13. If bearing lube oil drains temperature more than 110 oC. GT. will be tripped True or False?. ……………………………………………………………………………….. 14.Main Lube oil pump drive by motor True or False ?. ………………………………………………………………………………… 15.If we have alarm Lube oil pressure switch trouble and some one need to test pressure switch 63QA Lube oil pressure low ( Lube oil pressure low alarm ) can you permit they to test ? Yes or No. and tell the reason why you make decision on this choice ? ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………
