A substrate transport apparatus having a frame, a drive section and an articulated arm. The drive section has at least one motor module that is selectable for placement in the drive section from a number of different interchangeable motor modules. Each having a different predetermined characteristic. The articulated arm has articulated joints. The arm is connected to the drive section for articulation. The arm has a selectable configuration selectable from a number of different arm configurations each having a predetermined configuration characteristic. The selection of the arm configuration is effected by selection of the at least one motor module for placement in the drive section.