The versatility of compact excavators makes them a boon to many jobsites. With a quick switch between attachments, your customers can break concrete, load the demoed remains into a truck and grade the cleared site - all with the same machine.
"If a contractor determines he can do all these tasks with a single piece of equipment, that's pretty alluring," says Tom Connor, compact excavator product specialist at Bobcat.
In that sense, these smaller machines are more adept at multi-tasking than their big brothers. "I just don't see the same attachment utilization on larger excavators. Many times with larger excavators, attachments are dedicated, and even hard-plumbed. They do only one task for a given job, season or even lifetime. But with the compact sizes, contractors push the limit on attachments because it pushes the utilization of the machine."
But pushing the limits can create situations where these smaller carriers are asked to do too much. While you will want to make the best use of available power, you need to do so within the confines of the machine's specifications to prevent overloading, which can cause overheating and excessive and premature wear, as well as compromise stability.
Determine lift capacity
Bill Gearhart, assistant marketing manager/product manager at Yanmar, suggests you start by determining just how much your machine can lift. Some manufacturers print lifting limits on decals affixed directly to the machine. You can also find them printed in most product literature and owners' manuals.
Explain to customers that lift capacity will decrease as the boom extends. "If you're operating close to the machine, lift capacity will be greater," Gearhart says. "But as you extend the arm out to the side and up, the ability of the load to tip the machine will be greater."
Kendall Aldridge, national sales manager for IHI/Compact Excavator Sales LLC, suggests, "The contractor should always consult with the company they are renting or buying the [machine] from before using the unit in a lifting application," he says. "IHI's rated loads for lifting do not exceed 87 percent of hydraulic capacity or 75 percent of stability. The rated loads are on the conservative side to assure contractor safety."
Also, when choosing and using an attachment such as a bucket, consider the weight of the material your customer is working in, rather than strictly the volume that needs to be moved, adds Mike Conley, product manager, compact excavators at Komatsu. "There's a dramatic weight difference between a full bucket of cotton balls and a full bucket of wet clay," he says.
"It can be a challenge to know what a machine can handle," he continues. "There are a lot of factors that go into it."
Conley suggests reviewing the hydraulic capacity - flow and pressure - of the machine, especially when using attachments with high flow requirements, such as augers and breakers. "If it's a hydraulically driven attachment, you'll want to look at hydraulic flow capabilities of the machine and the requirements of the attachment," he says. "Mounting an attachment that's too large can cause it to overheat, which can be more of a concern with these compact machines because they have a limited reservoir for hydraulic fluid."
Mike Ross, Takeuchi, notes additional considerations in regards to tank size, as well as material. "The larger the hydraulic tank, the fewer the number of cycles the oil has to go through," he says. "The more times you cycle oil through the tank, the more wear and tear you put on the oil, the faster it breaks down and the more heat you create."
Ross adds that a steel tank can be a benefit to the cooling process because it disperses heat faster than one made from plastic. "Cooler oil won't put as much stress on pumps, valves, etc.," he says. "High-temperature hydraulic oil is definitely an enemy to pump life. If you can keep the oil at an even temperature, you'll find that your hydraulic pumps have a much longer life, and you won't have to change the oil as frequently."