SGA-3 is used for three types of governors: Porter, Proell, and Hartnell. By evaluating the governor’s response to input RPM, the non-sensitive zone and overall stability can be determined. To conduct a test, one of the above governors is mounted on the rotary disc via two bolts, then the RPM is increased so that the sleeve moves upward (the speed is properly and smoothly controlled due to the appropriate driver). Since the sleeve shaft is graduated, the speed corresponding to each mark should be recorded. From these recordings, the reciprocal speeds are obtained, allowing parameters such as governor sensitivity, non-sensitive zone and stability to be determined. If it is required to increase the sleeve mass, place some steel balls inside the basket and proceed as prescribed above. If it is necessary to replace the spring or change the governor stiffness, loosen the nut above the governor, place the spring on the sleeve, and then retighten the nut. Meanwhile, this apparatus is equipped with a protective transparent cover and limit switch to stop the test if the cover is not properly installed.