Systems and methods for protecting drill blades in high speed turbine drills

Jet motor for providing rotation in a downhole tool

Turbine for power generation in a drill string

Drive system

Bearing arrangement for a turbine rotor of a drill string turbine

Impeller arrangement

Jet motor for providing rotation in a downhole tool

Method and apparatus for extending flow range of a downhole turbine

Method and apparatus for shifting speeds in a fluid-actuated motor