Question 333Steam Plants - 1st Asst/Chief

The correct answer is B) uneven heat distribution in the rotor unit. Raising the vacuum on a main turbine unit without using the turning gear will result in uneven heat distribution in the rotor unit. This is because the rotor needs to be slowly rotated to ensure even heating and cooling as the vacuum is raised. Without the turning gear, the rotor can become unevenly heated, leading to potential damage to the rotor and turbine components. The other options are incorrect because: A) excessive time is not the primary issue, C) scoring of the rotor is a result of the uneven heat distribution, and D) overheating of the second stage air ejector is not directly caused by raising vacuum without the turning gear.