Question 569Steam Plants - Assistant Engineer

The correct answer is D) the amount of cooling water to the condenser is insufficient. The back pressure trip on a ship's service turbo-generator is designed to protect the turbine by tripping it when the condenser is not receiving enough cooling water. Insufficient cooling water causes the condenser pressure to rise, which in turn increases the back pressure on the turbine. This high back pressure can damage the turbine, so the back pressure trip automatically shuts down the turbine to prevent this. The other options are incorrect because they do not directly relate to the function of the back pressure trip. Low lubricating oil pressure, high gland seal leak off pressure, or excessive cooling water flow would not trigger the back pressure trip.