Gas Turbines’ Spare Rotor

Presented by ZAA / ZS

IntentGT Rotor ConfigurationBackground / History of Spare RotorIssues in Spare R RotorTrade OffSpare M-Prime RotorCurrent ScenarioFuture Action Plan

Keeping in mind 04 GTs Operation and revised sparing philosophy in that context demands spare rotor for GT-601, 602 & 603

Alternator Inductor Rotor16 Stage Compressor RotorJournal for brg # 1Journal for brg # 22nd Stage Turbine Wheel1st Stage Turbine Wheel

GT-603 was relocated from USA and up-rated from model L to R in 1997/1998.

In 1997, KGT-2501 was up-rated from model L to M Prime. Frame-5 M-Prime machine in Baton Rouge was bought. Rotor of that machine was by refurbished by GE.Presently this rotor is installed in KGT-2501.

A rotor of Model L from KGT-2501 was, therefore, a spare one.

Spare Rotor Philosophy:A spare rotor of KGT (process air compressor driver) should be available at site with additional benefit of being spare for the rest of the turbines.

In this context, GE responded that an R rotor can become spare for all 04 gas turbines.In 1999, L model rotor was sent to GE Meelsa for R up-rate as a common spare.The same rotor was received in 2001 as R rotor. So it was thought that this rotor is spare for KGT and GT-603.

In 2003, it was decided to up-rate GT-602 from LA to R using the same rotor received in 2001. Two glaring issues were revealed during GT-602 up-rate.No. of holes of the 2nd Stage Turbine Wheel end were 20 instead of 24There was increased clearance between 1st stage bucket and wheel indicating high wiggling or bucket rock issue which was completely overlooked by GE.

GE Contradicted their earlier stance that spare R rotor is compatible for KGT-2501 M-Prime.

GT-601GT-602GT-603KGT-2501Spare RotorModelLLARM-PrimeRSpare Rotor UseableOur ParadigmYESYESYESYESRealityNONONONOWhy?2nd Stage Turbine End Flange Bolt Holes24242024202nd Stage Wheel Diameter43.2"45.8"43.2"WigglingYES

R rotor was of no use, so spare rotor for M-Prime was needed the most as per revised sparing philosophy

So-called spare R rotor was sent to GE in 2005 and was received in April 2007.Twist lock arrangement in 1st stage buckets instead of lock pin.GE provided twist lock wheel at that time and lock pin design wheel could further delay refurbishment.

This rotor is still lying in safe custody with W/H.

GT-604 spare rotor is available but it cannot be used on any of the 04 GTs because of difference in type of coupling at both ends and difference in no. of holes i.e. 32.The spare rotor available for KGT-2501 can be used in this very machine only.As per 04 GTs operation, there is no spare rotor available for GT-601, 602 & 603.Each GT demands one separate spare rotor is present conditions.

GT-601GT-602GT-603KGT-2501Spare Rotor 1ModelLARRM-PrimeM-Prime1st Stage Bucket DesignLock PinLock PinLock PinLock PinTwist Lock1st Stage Wheel DesignLock PinLock PinLock PinLock PinTwist LockSpare Rotor UseableNoNoNoYES-2nd Stage Turbine End Flange Bolt Holes2424202424

Option-1Compilation of complete data of rotors and details sent to GE for a solution. ( Done )

Option-2Procure GT-603 Load Gear Coupling with 24 bolt holesReplace GT-603 2nd Stage Turbine Wheel with 24 bolt holes flange(This shall make GT-602 & 603 rotor common for both)Option-3Uprate GT-601 from LA to R.In addition to Option-2. (This shall make rotor common for all three GTsLook for a spare R rotor with scrap vendors or non-OEM vendors such as MJB, TSL etc. & prepare cost estimates.

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