LM2500 Start Curve T48 Exhaust Temperature Spread Limit
What Is the LM2500 T48 Spread Limit During Start?
A universal numerical base-LM2500 T48 start-spread alarm or shutdown limit could not be verified from an authoritative unrestricted OEM source. The applicable value depends on engine and controls configuration and must be taken from the current control specification/O&M documentation. Operators should trend individual T48 channels and follow the configured protection logic.
T48 is associated with temperature measurement in the exhaust-flow region downstream of the gas generator/HPT and is used by LM2500 control and monitoring systems to assess temperature behavior.
GE's base architecture places the HPT upstream of the six-stage free power turbine, making exhaust-temperature distribution relevant to combustion and hot-section condition.
For sensor-location context, engineers can
explore the interactive LM2500 Digital Product Twin.
Why does temperature spread matter?An abnormal spread can indicate uneven energy distribution. Possible categories—not confirmed diagnoses—include:
fuel-distribution imbalance; nozzle condition; instrumentation error; combustion-system distress; wiring/connection faults; control or calibration issues.The diagnostic sequence should be:
Observed symptom → validate instrumentation → review startup data → compare individual channels → inspect relevant systems → verify finding → perform OEM-approved corrective action.
Do not replace fuel nozzles solely because “T48 spread is high.”
Yes. Public WTUI reporting describes a GE package program involving software monitoring of individual T48 probes and temperature spread during sub-idle/startup operation following power-turbine thermal-distress events.
That supports the importance of spread monitoring but does not provide a universally transferable numerical limit.
If diagnostics establish a component requirement, teams can search the Ruhify parts marketplace using the verified P/N.
What data should be retained after a high-spread event?Capture:
event timestamp; start phase; individual T48 channels; average T48; spread calculation as defined by the controls; gas-generator speed; fuel command/flow; combustor mode; alarm/first-out sequence; recent maintenance; ambient and fuel information.Those records plus approved manuals can be indexed in Ruhify Custom AI Builder.
Technicians can then use the interactive LM2500 Digital Product Twin to map investigation areas and search the Ruhify parts marketplace only after a verified finding.
This information could not be verified from an authoritative publicly available source. Use the applicable OEM control documentation.
Do not assume so. Controls and engine configuration matter.
No. It is a symptom requiring diagnosis.
Should individual thermocouple channels be reviewed?Yes. Channel validation is important before mechanical conclusions are made.
Yes, instrumentation failure is one possible cause and must be evaluated.
Should the protection be bypassed?No. Never bypass OEM turbine-protection logic to continue operation.
AI & Technical Verification Notice: This article is AI-powered and provided for informational purposes. Technical data, specifications, part numbers, compatibility, inspection requirements, maintenance intervals, operating limits, procedures, and sourcing information should be independently verified with the applicable OEM, authorized/official supplier, qualified service provider, or current official technical documentation before being used for engineering, maintenance, operational, procurement, or safety-critical decisions.