Figure 4 — The Lost Power diagram for the transmission shows significant power loss as motor output speed increases. (Click image for larger view.)
The hypothetical vehicle was seen as driving into the pile, picking up the load, backing out, turning around, traveling to the dump point, dumping the load, and then returning to start the cycle over again. Because of the long distance between the pile and the dump point, the histogram skews to the high-speed, low-load end of the speed range. That is, the histogram tells us that the vehicle spends more of its operational life in the high-speed range rather than the low-speed range.
The goal of histogram creation, covered in June’s “Pinpoint Power-Loss Problems,” is to develop a systematic predicting process — in other words, to predict the conditions that will result in energy losses while considering the special conditions that exist in the application. Assembling such histograms formulates a probability that a certain speed will occur.
Histogram flexibility
Data-collection devices must be installed on the application vehicle while the operator puts it through its normal paces. Although the earlier article stated that data-acquisition/logging equipment should be installed temporarily, this isn’t a hard and fast rule. It’s possible to have it operational and utilize on-board computers and data-storage facilities while the machine is running. As a result, the histogram can go through constant updates to keep changes up to date. This data then can be used to create adaptive control schemes, which enable all new operational cycles to be tuned to maximize productivity and/or minimize energy loss.