GE Frame 5 Service Manual

27
inspection of all of the major flange-to-flange components of 
the gas turbine, which are subject to deterioration during normal 
turbine operation. This inspection includes previous elements of the 
combustion and hot gas path inspections, and requires laying open 
the complete flange-to-flange gas turbine to the horizontal joints, 
as shown in Figure 32.
Removal of all of the upper casings allows access to the 
compressor rotor and stationary compressor blading, as well as 
to the bearing...

28
•	Visually inspect compressor and compressor discharge case
hooks for signs of wear.
•	 Visually inspect compressor discharge case inner barrel.
•	 Inspect exhaust frame flex seals, L-seals, and horizontal joint
gaskets for any signs of wear or damage. Inspect steam gland
seals for wear and oxidation.
•	 Check torque values for steam gland bolts and re-torque
to full values.
•	 Check alignment – gas turbine to generator/gas turbine to
accessory gear.
•	 Inspect casings for signs of casing flange...

29
Operating Hours
Nozzle Construction
Severe Deterioration
10,00020,00030,00040,00050,00060,00070,00080,000
New Nozzle
Acceptance Standards
Repaired Nozzle
Min. Acceptance 
Standard 1st
Repair
2nd
Repair
3rd
Repair
Repair Cost ExceedsReplacement CostWithout Repair
Figure 38 .  First-stage nozzle repair program: natural  gas fired – continuous dry – base load
Type of InspectionType of 
hours/
starts
Hours/Starts
6B 
7E  9E
MS3002K MS50 01PA MS5002C, D6B
 .037E .0

3
 (6)9E .03 (7)
Combustion (Non-DLN)...

30
Inspection Intervals
In the absence of operating experience and resulting part 
conditions, Figure 39 lists the recommended combustion, hot   
gas path and major inspection intervals for current production 
GE turbines operating under typical conditions of natural gas fuel, 
base load, and no water/steam injection. These recommended 
intervals represent factored hours or starts calculated using 
maintenance factors to account for application specific operating 
conditions. Initially, recommended...

31
Figure 40 . Combustion inspection hours-based maintenance factors
Syngas units require unit-specific intervals to account for unit-
specific fuel constituents and water/steam injection schedules.   
As such, the combustion inspection interval equations may not 
apply to those units. 
Hours-Based Combustion Inspection 
Where:
i   = Discrete Operating mode (or Operating Practice   
    of Time Interval)
t
i  =  Operating hours at Load in a Given Operating mode
Ap
i  =  Load Severity factor
    Ap  =...

32
Hot Gas Path Inspection Interval
The hours-based hot gas path criterion is determined from the 
equations given in Figure 42. With these equations, a maintenance 
factor is determined that is the ratio of factored operating hours 
and actual operating hours. The factored hours consider the 
specifics of the duty cycle relating to fuel type, load setting and 
steam or water injection. Maintenance factors greater than one 
reduce the hot gas path inspection interval from the baseline 
(typically 24,000...

33
Figure 44 describes the procedure to determine the hours-
based maintenance criterion. Peak load operation is the primary 
maintenance factor for the F-class rotor and will act to increase 
the hours-based maintenance factor and to reduce the rotor 
maintenance interval. For B/E-class units time on turning gear also 
affects rotor life.
The starts-based rotor maintenance interval is determined from the 
equations given in Figure 45 . Adjustments to the rotor maintenance 
interval are determined from...

34
The baseline rotor life is predicated upon sound inspection results 
at the major inspections. For F-class rotors the baseline intervals 
are typically 144,000 hours and 5,000 starts. For rotors other than 
F-class, the baseline intervals are typically 200,000 hours and 
5,000 starts. Consult unit-specific documentation to determine if 
alternate baseline intervals or maintenance factors may apply.
Personnel Planning
It is essential that personnel planning be conducted prior to an 
outage. It should...

35
References
Jarvis, G., “Maintenance of Industrial Gas Turbines,” GE Gas Turbine 
State of the Art Engineering Seminar, paper SOA-24-72, June 1972.
Patterson, J. R., “Heavy-Duty Gas Turbine Maintenance Practices,” 
GE Gas Turbine Reference Library, GER-2498, June 1977.
Moore, W. J., Patterson, J.R, and Reeves, E.F., “Heavy-Duty Gas 
Turbine Maintenance Planning and Scheduling,” GE Gas Turbine 
Reference Library, GER-2498; June 1977, GER 2498A, June 1979.
Carlstrom, L. A., et al., “The Operation and...

36
Appendix
A .1) Example 1 – Hot Gas Path Maintenance 
Interval Calculation
A 7E.03 user has accumulated operating data since the last hot  
gas path inspection and would like to estimate when the next   
one should be scheduled. The user is aware from GE publications 
that the baseline HGP interval is 24,000 hours if operating on 
natural gas, with no water or steam injection, and at base load.   
It is also understood that the baseline starts interval is 1200,   
based on normal startups, no trips, no...