WRENCH-BOX 6V4154 - Caterpillar

RAC module utilizes the VIMS to determine the weight of the payload and the cycle times. The RAC module samples data at a rate of ten times per second. Then, the RAC module calculates the relative severity of each haul cycle. The RAC module calculates the stress that is present on major components of the truck as a way of monitoring the condition of the haul roads. This calculation indicates when repairs to the haul road are needed. This information can be used in order to assess the various design configurations of the haul road. This information can be used to determine the design configurations that have the least effect on the life of the truck. Stress levels that are above the design specification of the machine can be detrimental to the items that are listed below:
Tires and rims
Frame structures
Suspension Components
Components of the power trainRoads that are properly designed for the hauling units will also provide the benefits that are listed below:
Ensure the shortest possible cycle time.
Minimize operator fatigue.
Minimize stress on the truck.
Operate within the design life cycle of the truck (refer to the Haul Road Benchmark Graph)The RAC data represents the summation of the measured fatigue equivalent truck stresses that result from the combination of actual payload weight and the ground speed during each haul cycle. This data is compared to Caterpillar's analysis of the calculated fatigue under the same conditions. The RAC reports provide an indication of the effect that the payload cycles may have on the design life of the truck. The RAC data is expressed in numbers that are related to the relative stresses that are called the Fatigue Equivalent Load Analysis (FELA). The RAC collects the Rack data, the Pitch data and (if equipped) the Bias data. Rack - This is the twisting of the truck due to uneven dynamic forces. A "High Rack" condition can occur when a truck that is traveling loaded hits a pothole on a poorly maintained haul road. High dynamic forces can be transmitted into the frame, tires and other major components. This will cause reduced component life. An example of a "High Rack" condition is when a fully loaded truck is parked with the right front tire in a pothole and the left rear tire on an incline (burm). Pitch - This is the rocking force on the truck, from the front to the rear of the truck. "Pitch" forces occur in the situations on the haul road that are listed below:
Hard braking
Hard turns
Bumps
Dips that are the width of the Truck
Travelling uphill
Travelling downhillBias - (If equipped) This is the side to side force on the truck. Bias can be due to improper loading. Drastic crowning of the haul road may also cause a Bias event. Bias occurs when the difference between both left hand (front and rear) suspension cylinders versus the right hand (front and rear) suspension cylinders exceeds recommended limits. "Bias" events provide an indication of improper loading techniques and/or haul road issues. If either