What is a major difference between critical RPMs on an SSTG and an auxiliary turbine?

The major difference between critical RPMs on a Speed Governor Turbine Generator (SSTG) and an auxiliary turbine relates to how the critical RPMs are defined in relation to their operating speeds. For SSTGs, critical RPMs occur at 20 to 25 percent below normal operating speed. This is significant because it indicates the specific range where the turbine is susceptible to vibrations and resonance effects, which can lead to mechanical failure or inefficiencies in operation.

Operating at these critical speeds can expose the turbine to conditions where the natural frequency of the turbine structure aligns with the forcing frequencies generated during operation, potentially leading to excessive vibration. This makes monitoring and controlling the RPMs in this range crucial for maintaining the integrity and performance of SSTGs.

In contrast, critical RPMs for auxiliary turbines may not follow the same threshold and operational characteristics. Understanding the specific RPM benchmarks for different types of turbines aids in ensuring safe and effective machinery operation within these systems.