SEAL 4431363 - Caterpillar

Read this entire manual and all other publications pertaining to the work to be performed before installing, operating, or servicing this equipment. Practice all plant and safety instructions and precautions. Failure to follow instructions can cause personal injury and/or property damage.The engine, turbine, or other type of prime mover should be equipped with an overspeed (overtemperature, or overpressure, where applicable) shutdown device(s), that operates totally independently of the prime mover control device(s) to protect against runaway or damage to the engine, turbine, or other type of prime mover with possible personal injury or loss of life should the mechanical-hydraulic governor(s) or electric control(s), the actuator(s), fuel control(s), the driving mechanism(s), the linkage(s), or the controlled device(s) fail.
Introduction
The basic PSG (Pressure Compensated Simple Governor) is a hydraulic speed governor with buffer type compensation. It is normally isochronous, that is, if the engine is not overloaded it maintains the same speed regardless of load, except momentarily at the time load change occurs.
Figure 1-1. Basic PSG GovernorThe governor uses engine lubricating oil or an oil supply from a separate sump furnished by the engine manufacturer. If the latter is used, lift should not exceed 300 mm (12 inches) and a foot valve should be furnished. The torque, work capacity, and maximum work values of the PSG governor are based on 172 kPa (25 psi) supply oil pressure to the governor. These values can vary depending on the supply oil pressure.The standard PSG cover provides for an interior vertical return-spring. The cover includes a bracket for the Pittman PM (Permanent Magnet) speed-setting motor. PSG governors without a motor have a low-speed stop screw installed in the cover. See Figure 1-1 for external features of the PSG.Special Features
The normal PSG has a cast iron case and base and an aluminum cover. For many years, PSGs were built with aluminum cases. Aluminum case PSGs are still available for special purposes. Aluminum case PSGs are described in Manual 37013.PSGs are built in many special configurations to meet the unique needs of various engine manufacturers. Most of these special features are described in Chapter 6 of this publication. The PSG uses hydraulic pressure to drive the terminal shaft in only one direction. If an internal return spring is not used, a spring must be installed before the engine is started.References
Sales, service, and product information for the PSG Governor can be obtained from Woodward locations listed on the back cover of this manual. Other Woodward publications that may prove helpful are: