At what vacuum is the generator brought up to speed after starting an SSTG?

When starting a Ship Service Turbine Generator (SSTG), it is crucial to bring the generator up to speed at a specific vacuum level to ensure optimal operation and prevent damage to the turbine. The correct vacuum level for this process is typically around 15 inches of mercury.

At this vacuum level, the turbine can achieve the necessary rotational speed while minimizing back pressure on the exhaust side, leading to a more efficient performance and reducing the risk of mechanical failure. This vacuum level helps maintain a balance that allows for smooth acceleration and the ability to handle the load demands that come from the electrical systems on board.

Understanding the relationship between vacuum levels and turbine operation is important for machinist mates, as improper vacuum levels could result in inadequate performance, increased wear and tear, or outright failure of the generator system. Thus, the 15 inches of mercury is the standard and optimal vacuum level for this critical starting procedure.