OM3237 02/10 Operation - Section 32 Operator Cab and Controls Page 32-7 Retard Speed Control (RSC) Switch Retard speed control switch (11, Figure 32- 6) turns the system off or on. Push the knob in to turn the system off, and pull the knob out to turn the system on. To adjust the RSC control, pull switch (11) to the ON position. Start with dial (12) rotated toward the fastest speed while driving the truck at the desired maximum speed. Relax the throttle pedal to let the truck coast, and turn the RSC dial slowly counterclockwise until dynamic retarding is activated.
Dynamic retarding will now be activated automatically anytime the set speed is reached, the RSC switch is ON, and the throttle pedal is released. . With the RSC switch in the ON position and the dial adjusted, the system will function as follows: As the truck speed increases to the set speed and the throt- tle pedal released, dynamic retarding will apply. As the truck speed tries to increase, the amount of retarding effort will automatically adjust to keep the selected speed. When the truck speed decreases, the retarding effort is reduced to maintain the selected speed.
If the truck speed continues to decrease to approximately 5 kph (3 mph) below the set speed, dynamic retarding will turn off automatically. If the truck speed must be reduced further, the operator can turn the dial to a new setting or depress the retard pedal. Retard Speed Control (RSC) Dial RSC dial (12, Figure 32-6) allows the operator to vary the downhill truck speed that the retard speed control system will maintain when descending a grade. If the operator depresses the retard pedal, and the retard effort called for is greater than that from the automatic system, the demand from the pedal will override the RSC.
When the dial is rotated counterclockwise toward the turtle symbol, the truck will descend a grade at lower speeds. When the dial is rotated clockwise toward the rabbit symbol, the truck speed will increase. The throttle pedal position will override the RSC set- ting. If the operator depresses the throttle pedal to increase the truck speed, dynamic retarding will not activate unless the truck overspeed setting is reached, or the retard pedal is used. When the throt- tle pedal is released, dynamic retarding will activate at the RSC preset speed. The RSC control will main- tain the truck speed at the preset limit. IN OFF OUT ON