An Excavator (sometimes called a digger) is a piece of heavy construction equipment. Excavators are used to dig in the ground or to move large objectsAt the base of the machine, it usually has two tracks to move it. Above the tracks is a platform that rotates (180° or 360° degrees). The operator sits in a cab and controls the excavator. One set of controls moves the machine forward and backward. Another set of controls operates the arm and the tilting bucket. hydraulic fluid, hydraulic cylinders and hydraulic motors control the machine. 