OM4033.2 Maintenance - Section 4 Automatic Lubrication System 4-17 Pressure Failure Detection Circuits: 1. When the lubrication cycle is initiated, 24VDC flows through relay RB6-K4 (8, Figure 4-4) N.C. contacts to a 1 minute delay timer (7). turning on the “Low Lube System Pressure” warning lamp on the overhead display. After RB6- K2 relay energizes, it will energize relay RB6-K6 (6). 2. If the system is operating normally, grease pres- sure at the rear axle injector bank will rise to pres- sure switch (9) setting of 2000 psi (13.8 MPa) and energize relay RB6-K4 (7), removing 24VDC from the delay timer. 4.
Once RB6-K6 is energized, it will latch and remain energized as long as the keyswitch is on. In addi- tion, RB6-K2 will also remain energized and the Low Lube Pressure Warning lamp will remain on to notify the operator a problem exists and the system requires service. 3. If a problem occurs and the system is not able to attain 2000 psi (13.8 MPa), the delay timer (7) will energize relay RB6-K2 (10) after 60 seconds, 5. FIGURE 4-4. 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: N.O. 5. Grease Pump Solenoid Valve 6. Relay K6 (On Relay Board RB6) 7.
Time Delay Module 8. Relay K4 (On Relay Board RB6) 9. Pressure Switch; N.O. (Rear Axle Injector Bank) 10. Relay K2 (On Relay Board RB6) 11. Low Grease Pressure Warning Lamp (On Overhead Display Panel) 12. Relay K1 (On Relay Board RB6) 13. Test Switch