Which bearings are located in the sump of the GTM?

The correct choice highlights the bearings that are housed within the sump of the Gas Turbine Module (GTM). The sump is a crucial area in gas turbine systems as it often contains lubricating oil, and the bearings listed support various components of the turbine while providing critical lubrication to minimize wear and friction between moving parts.

Specifically, the presence of bearings 3R, 4R, 4B, 5R, 6R, 7B, and 7R in the sump indicates that these components play a reliable role in maintaining the structural integrity and functionality of the turbine's mechanical operations. Including both radial and ball bearings (noted as R and B) demonstrates the diversity of the bearing types used in this strategic location, accommodating the multidirectional loads exerted on the turbine as it operates.

Moreover, this selection of bearings indicates a comprehensive design that ensures various parts of the gas turbine system receive adequate support and lubrication, enhancing performance and longevity. The inclusion of multiple bearings also addresses the need for effective load distribution throughout the system, which is vital in high-speed applications like a gas turbine. This understanding is essential for technicians working to maintain and troubleshoot the gas turbine system effectively.