GLASS 3786578 - Caterpillar

Key Switch In STOP Position
DC Schematic Of Key Switch In STOP PositionWhen the keyswitch (KS) is turned to the STOP position (line 10), KS contacts B and R (lines 11 and 13) open and slave relay (SR1) (line 13) is de-energized. SR1 contacts 30 and 87 (line 7) open and fuel solenoid (FS) (line 7) is de-energized. Fuel is no longer provided to the engine.Engine Shutdown Operation
The engine can be shutdown manually or automatically. The most common method of shutting down the engine is by manually turning the key switch to the STOP position. For more information on this method, see the topic Key Switch In STOP Position.When any one of the following conditions exist, the corresponding fault light will illuminate, the corresponding relay will energize and the engine will shutdown automatically.* If the engine should overspeed as determined by the electronic speed switch (ESS).* If the engine water temperature should rise above the upper limit of the water temperature switch (WTS).* If the engine oil pressure should fall below the low limit of the engine oil pressure switch (OPS).* If a shutdown condition should occur for the spare fault as determined by the customer.Each of these shutdown methods (except spare fault) are described in the topics which follow. The conditions required for the spare fault shutdown are determined by the customer. However, the actual shutdown operates the same as the other faults.Engine Shutdown Caused By Oil Pressure Fault
DC Schematic Of Engine Shutdown Caused By Oil Pressure FaultWhen the key switch (KS) returns to RUN from the START position, KS contacts B and R (lines 11 and 13) close. The slave relay (SR1) (line 13) is now energized. SR1 contacts 30 and 87 (line 7) close to keep the fuel solenoid (FS) energized. Fuel is now provided to the engine.The arming delay timer (ADT) (line 15) is also energized when the KS is in the RUN position. The ADT controls the amount of time that the oil pressure shutdown circuit is disabled after engine cranking. When the ADT is first energized a 15 second delay begins before the arming relay (AR) (line 15) is energized. After the 15 second delay the ADT energizes the AR. Contacts 4 and 7 of the AR (line 43) close. The oil pressure relay (OPR) (line 43) and the oil pressure light (OPL) (line 44) can now respond to a closed OPS (low oil pressure). During normal conditions, the 15 second delay allows the initial oil pressure to build-up which opens the oil pressure switch (OPS) (line 43).If initial oil pressure does not build-up in the 15 second time delay, the OPS (line 43) will remain closed. Also, AR contacts 7 and 4 (line 43) are now closed. The circuit to the oil pressure relay (OPR) (line 43) and the oil pressure light (OPL) (line 44) is now complete. The OPR and the OPL are energized. OPR contacts (line 44) close and the OPR is latched. Also, OPR contacts (line 47) close to