The Low-Speed, High-Torque (LSHT) radial piston hydraulic motor was first introduced in 1896. While it was relatively efficient, very little improvement of the basic design was seen for almost 60 years. As a consequence, the acceptance of the units as a viable alternative to the conventional drive system of a high speed power source coupled to a multi-stage speed reducer was very limited.It was not until the mid 1950's that the second generation designs produced commercially available models that had improved both reliability and performance to the point of gaining true market acceptance. No longer seen as an alternative, the LSHT motor drive was recognized as an improvement over the conventional system in a rapidly expanding number of applications.In subsequent years the numbers of manufacturers grew, each with their own approach to applying the radial piston concept. However, hydraulic pump technology outpaced LSHT motor technology and machine designers found themselves with highly efficient, high pressure pumps and low to moderate pressure motors. It has only been in the past couple of years that the LSHT radial piston motor developments have permitted this vital system drive to keep pace with the modern high pressure axial piston pumps. Today, the hydraulic system designer can take full advantage of the power and torque capabilities in a compact, efficient drive system.This evolution, as it relates to the design and performance of the new Rotary Power SMA high pressure LSHT motor will be reviewed from the concept to the applications. It is the new generation.