OM4206 06/06 Maintenance - Section 42 Automatic Lubrication System Page 42-7 Pressure Failure Detection Circuits 1. When the lubrication cycle is initiated, 24VDC flows through relay RB6-K4 (8, Figure 42-6) N.C. contacts to one minute time delay module (7). 3. If a problem occurs and the system is not able to attain 13.8 MPa (2000 psi), then time delay module (7) will energize relay RB6-K2 after 60 seconds, turning on the Low Lubrication Sys- tem Pressure warning lamp on the overhead display. After RB6-K2 energizes, it will ground the coil of RB6-K6 and allow it to energize. 2.
If the system is operating normally, grease pres- sure at the rear axle injector bank will rise to pressure switch (9) setting of 13.8 MPa (2000 psi), closing the switch contacts and energizing relay RB6-K4 (8), removing 24 Volts from the time delay module. The timer is then reset and no current will flow from the timer output terminal. 4. Once RB6-K6 is energized, it will latch and remain latched as long as the key switch is on. Also, RB6-K2 will remain energized and the Low Lubrication Pressure Warning light will remain on to notify the operator a problem exists and the system requires service. 5. The warning circuits are reset when the key switch is turned off. FIGURE 42-6.
ELECTRICAL SCHEMATIC 1. Lubrication Cycle Timer 2. Circuit Breaker 33 (Power Distribution Module in Cab) 3. Circuit Breaker 35 (Power Distribution Module in Cab) 4. Pressure Switch (On Grease Pump) - 20685 kPa (3000 psi) 5. Grease Pump Solenoid Valve 6. Relay Board 6, Relay K6 7. Time Delay Module 8. Relay Board 6, Relay K4 9. Pressure Switch (Rear Axle Injector Bank) - 13789 kPa (2000 psi) 10. Relay Board 6, Relay K2 11. Auto Lubrication Low Pressure Warning Lamp 12. Relay Board 6, Relay K1 13. Manual Override