🔍 Key Concepts

• GE LM2500 gas turbine start sequence and permissive signals • Typical fuel supply pressure requirements for gas turbine start-up • Role of gas generator (GG) speed limits and trip/alarm resets before starting

💭 Think About

• Think about what conditions must exist so that a gas turbine can safely receive fuel and accelerate from rest without damage or flameout. • Ask yourself which of these conditions are related to protecting the turbine from overspeed, surge, or loss of control during start. • Consider whether any one of these conditions alone would be enough for a safe, automatic ‘normal’ start on a modern, interlocked control system.

✅ Before You Answer

• Verify the normal minimum fuel supply pressure specified for LM2500 start permissive (compare 8 psig with what you’ve studied). • Confirm the typical maximum GG speed allowed before initiating a start attempt and why trips must be reset first. • Check whether the bleed air valve position is monitored as a start permissive on LM2500 systems you’ve studied, or only as an operating parameter.