TRACK GROUP 6T1186 - Caterpillar

Operation of the Engine Speed Switch
Illustration 1 g00562933
The speed switch accepts a signal from the magnetic pickup. The magnetic pickup is mounted on the engine. The speed switch determines the engine speed from the signal. The speed switch provides contacts for the following list of conditions:
"Crank Terminate"
Engine Oil Step Pressure
Engine Overspeed
Nine Second Time DelayDefinitions
"Engine Overspeed" - The relay energizes when the engine speed reaches 113% of rated speed. The N.O. contact will remain closed until the speed is less than 113% of rated speed. The reset button on the speed switch must be pushed. The overspeed light will remain illuminated until the overspeed contact is reset and until the speed is less than 113% of rated speed."Crank Terminate" - The relay energizes when the engine speed reaches 170 RPM. The crank terminate relay is used in order to indicate that the engine is running. The N.O. contact 10 will remain closed until the engine speed is zero for two seconds."Engine Oil Step Pressure" - Nine seconds after the engine reaches 75% of rated speed setting, terminal 13, terminal 14, and terminal 15 energize. The contact is used in order to enable the high speed low oil pressure shutdown contactors and the alarm contactors. The N.O. contact 13 remains closed until the engine speed is less than 75% of rated speed."Nine Second Time Delay" - Nine seconds after the voltage is removed, terminal 16, terminal 17, and terminal 18 de-energize. This occurs after crank terminate speed is reached. The time delay contact is used in order to enable the alarms and the shutdowns that require the engine to be running. The N.C. contact stays closed until the engine speed is zero for 2 seconds. Note: If an overspeed condition occurred, the reset button must be pressed in order to start the engine.