OM3020.2 12/99 Operation - Section 3 Operator Cab and Controls Page 3-17 INSTRUMENT PANEL The Instrument Panel (7, Figure 3-1) includes a wide variety of switches, gauges, and indicators. Refer to INSTRUMENT PANEL AND INDICATOR LIGHTS, for a detailed description of function and location of these components. GRADE/SPEED CHART higher-than-continuous rate for a short period of time beyond which the system would become over-tem- perature. The Grade/Speed chart (8, Figure 3-1 & shown below) provides the recommended MAXIMUM truck speeds for descending various grades with a fully loaded truck.
If the vehicle is operated at short-term grade and speed limits for a period of time greater than three minutes, the retarding effort may begin to reduce, resulting in vehicle acceleration. The service brakes are available to slow the truck within the continuous level. This reduction in retarding effort will be gradual as the vehicle moves from the short-term limits to the continu- ous limits. This decal may change with OPTIONAL truck equip- ment such as: wheelmotor drive train ratios, retarder grids, tire sizes, etc. ALWAYS refer to this decal in the operator’s cab , and follow these recommendations for truck operation.
The operator should reference this chart before de- scending any grade with a loaded truck. Proper use of Dynamic Retarding will maintain a safe speed. The “three-minute” curve is a minimum and the actual time limit could be greater. Ambient temperature, baro- metric pressure and recent motor power levels can affect this number. The three-minute rating will successfully accommo- date most downhill loaded hauls. It is necessary to divide haul road grade segment length by allowable speed to determine actual time on grade. If actual time on grade exceeds the allowable amount, the grade will need to be negotiated at the continuous speed.
DO NOT exceed these recommended MAXIMUM speeds when descending grades with a loaded truck. RADIO SPEAKERS Radio Speakers (9, Figure 3-1) for the AM/FM Stereo radio are located at the far left and right of the overhead panel. WARNING ALARM BUZZER This alarm (10, Figure 3-1) will sound when activated by any one of several truck functions. Refer to INSTRUMENT PANEL AND INDICATOR LIGHTS, for a detailed description of functions and indicators that will activate this alarm. Two lists are provided, one a continuous rating and the second a short-term (3-minute) rating. Both lists are matched to a truck at maximum Gross Vehicle Weight.
CAB RADIO This panel will normally contain an AM/FM Stereo radio (11, Figure 3-1). Refer to Section 6, Optional Equip- ment, for a more complete description of the radio and its functions. The continuous numbers on the chart indicate the combination of speeds and grades which the vehicle can safely negotiate for unlimited time or distance. The short-term (3-minute) numbers listed on the chart indicate the combination of speeds and grades which the vehicle can safely negotiate for three minutes. These speeds are faster than the continuous values, reflecting the thermal capacity of various system com- ponents.
System components can accept heating at a Individual customers may use this area for other pur- poses, such as a two-way communications radio. Warning Lights Dimmer Control This control knob (12, Figure 3-1) permits the operator to adjust the brightness of the Warning Indicator Lights.