VALVE AS-RELIEF 5288393 - Caterpillar

EARLIER PSG GOVERNOR
1. Bracket. 2. Pivot pin. 3. Output shafts.Speed droop is the difference between no load rpm and full load rpm. This difference in rpm divided by the full load rpm and multiplied by 100 is the percent of speed droop. The speed droop of the PSG governor can be adjusted. The governor is isochronous when it is adjusted so that the no load and full load rpm is the same. Speed droop permits load division between two or more engines that drive generators connected in parallel or generators connected to a single shaft.Speed droop adjustment on PSG governors is made by movement of pivot pin (2). When the pivot pin is put in alignment with the output shafts, movement of the output shaft lever will not change the force of the speeder spring. When the force of the speeder spring is kept constant the desired rpm will be kept constant. See PILOT VALVE OPERATION. When the pivot pin is moved out of alignment with the output shafts, movement of the output shaft lever will change the force of the speeder spring proportional to the load on the engine. When the force of the speeder spring is changed the desired rpm of the engine will change.On earlier PSG governors the cover must be removed to adjust the speed droop. Later models have an adjustment lever outside the governor connected to pivot pin (2) by link (4).
LATER PSG GOVERNOR
2. Pivot pin. 4. Link.Shutoff And Alarm System Components
Oil Pressure Switch
Micro Switch Type
The oil pressure switch is used to give protection to the engine from damage because of low oil pressure. When oil pressure lowers to the pressure specifications of the switch, the switch closes and activates the fuel shutoff solenoid.On automatic start/stop installations, this switch closes to remove the starting system from the circuit when the engine is running with normal oil pressure.The switch for oil pressure can be connected in a warning system for indication of low oil pressure with a light or horn.As pressure of the oil in bellows (6) becomes higher, arm (4) is moved against the force of spring (3). When projection (10) of arm (4) makes contact with arm (9), pressure in the bellows moves both arms. This also moves button (8) of the micro switch to activate the micro switch.
OIL PRESSURE SWITCH (Micro Switch Type)
1. Locknut. 2. Adjustment screw. 3. Spring. 4. Arm. 5. Spring. 6. Bellows. 7. Latch plate. 8. Button for micro switch. 9. Arm. 10. Projection of arm.Some of these switches have a "Set For Start" button. When the button is pushed in, the micro switch is in the START position. This is done because latch plate (7) holds arm (9) against button (8) of the micro switch and the switch operates as if the oil pressure was normal. When the engine is started, pressure oil flows into bellows (6). The bellows move arm (4) into contact with latch plate (7). The latch plate releases the "Set For Start" button