Equipment Type

Rediscovering The Wheeled Excavator's Versatility

This new Hyundai did everything professional operator Gene Held asked of it

April 01, 2005

 

Hyundai 200W-7
Several of the Hyundai's small design details impressed professional operator Gene Held: wear strips on the back of the boom that allow pinching concrete slabs without marring the boom; outrigger-cylinder covers that keep debris off the rods; and guards that keep rocks from lodging between tires.
200W-7
The 200W-7's hydraulic implement circuits operate at 4,690 psi, and its twin, variable-displacement hydraulic pumps deliver 58.1 gpm. According to Held, the machine is a strong trencher.
200W-7
The 200W-7 excavator demonstrated strong lifting capability, exhibiting stability even in over-the-side maneuvers.
200W-7
It just makes sense to use the power of the digging mechanism for backfilling, said Held, even though the machine had a blade.
200W-7 Cabin
The excavator has a pleasant, functional cabin with lots of glass for good visibility. The control monitor, however, offered a few too many choices to suit Held.
200W-7
Held commented favorably about the 200W-7's on-rubber digging ability, both over the end and over the side.

 

With more than 30 years in the International Union of Operating Engineers, Gene Held, an instructor at Local 150's Apprenticeship and Skill Improvement facility in Plainfield, Ill., is proficient on just about any type of construction machine. But Gene's specialty is sharing his expertise with students learning to use backhoe-loaders and hydraulic excavators. So, it was to Gene we turned to help us evaluate a brand-new wheeled excavator that Hyundai kindly loaned us for this installment of Hands-On Earthmoving.

Held told us that he had operated a wheeled excavator for nearly five years during a stint with a contractor, mostly setting sewer and water pipe with it.

"The contractor I was working for was so taken by how much the machine did," says Held, "that he bought two more."

Our Hyundai, a model 200W-7, arrived at Local 150's facility with a front outrigger, rear blade, 1.05-cubic-yard bucket, 7 foot-10 inch digging arm (shorter and longer versions are available) and a pair of 10.00–20 tube-type tires at each corner. Weighing slightly more than 45,000 pounds, the 200W-7 has a Cummins B5.9-C diesel engine rated at 153 net horsepower. Its hydrostatic drive system uses a two-speed, axial-piston hydraulic motor, which drives through a gearbox and propeller shafts to power conventional planetary axles front and rear.

Considering the concept

"In my opinion," said Held, "I think the rough-terrain configuration of the wheeled excavator, like this Hyundai, is better suited to off-road work than an excavator mounted on a truck chassis. I sometimes had my machine up to its wheel hubs in mud, but you could always use the digging mechanism to move the machine over and drive out. But if I were buying a wheeled excavator, I'd want outriggers front and back to get the most potential from it. The blade is okay, but not really that useful."

Held put the 200W-7 to work initially by opening about 30 feet of trench, 4 feet deep, in some reasonably tough material. He had both the outrigger and the blade deployed, but preferred to dig over the blade-end of the machine.

"The blade is closer to the machine than the outrigger box, so you can bring the bucket in farther. Plus, placing the outrigger box behind you gives added counterweight. The blade also digs in and stops the machine from being pulled toward the trench. But, everything considered, I still think you're better off with an outrigger at each end."

Powerful. But too many power-mode choices?

At the end of the trenching run, we asked Held for his impressions. He gave the machine high marks for its digging power, saying that it had excellent breakout force in some really tough digging he encountered. We asked, too, about his take on the overall operator's environment.

"The cab layout is excellent — the control levers are well placed and comfortable to use — and the cabin is nicely appointed. Getting on and off the machine is no problem, and the front glass stores easily. The steering-wheel console telescopes and tilts, that's handy, but the steering wheel is still a blind spot into the trench. But, obviously, it has to be there."

Having worked with Held before on excavator evaluations, we knew that he's not a big fan of selectable modes, preferring instead that the machine simply deliver all the power it has, then leave the control to him. But in the interest of the evaluation, he gave the Hyundai's multiple-choice monitor a fair try.

The 200W-7 has three work modes, which automatically adjust its hydraulic priorities for given tasks. The "heavy" mode favors boom speed, "general" favors swing speed, and "breaker" sets up the system for a hydraulic hammer.

"I preferred the boom-priority mode when I was trenching," said Held. "The machine does swing a bit faster in the general mode, but it's plenty fast enough in the other. If you swing these machines too fast, you could get off balance, because they're not as stable as a track machine. So far, though, I have no complaints about stability."

The 200W-7 also allows choosing between two power modes — high and standard — which we assume adjust engine speed and pump performance. Held tried both.

"The high-power mode has a slight edge, but I really don't think there's a marked difference in performance between the two," he said, "except that in the standard mode you get a drop in engine speed. Maybe fuel consumption would be somewhat less in the standard mode."

The machine also has a third choice — the user mode — that essentially allows customizing engine and pump settings (which the machine memorizes) to suit a particular operator. Held doubted that most operators would take the time to learn how to make these adjustments.

To complete the trenching exercise, Held backfilled, basically with the bucket, but saved just a bit of work for the blade.

"You're just defeating your purpose if you choose to use that small blade for backfilling, when you have all that power out in front of you. The blade might be good for minor cleanup work, but it's so close to the machine that it's hard to see the cutting edge, and so, it's difficult to control."

Lift, travel, and on-rubber digging

Our evaluation of the Hyundai also included traveling, stationary lifting, pick-and-carry and on-rubber digging.

Because the 200W-7's operator's manual was a little vague in some areas, Held needed a few minutes to figure out the machine's travel system, but quickly got the hang of it. The "W/T" switch on the forward console, he said, allows selecting a work or travel configuration. In "travel," hydraulic functions are deactivated and the "high-speed" choice on the monitor can be selected. In the work mode, hydraulic functions are activated, but speed is limited.

"It's a good roading machine," said Held. "Steering and braking are excellent, and the high-speed mode lets you get around the site quickly."

Of some initial concern, however, was the latching mechanism adjacent to the service-brake treadle. A close reading of the manual indicated that the operator must be careful to depress both the latch and the treadle during routine braking. Pushing only the treadle to its full stroke, the manual cautioned, would lock the service brake.

"I was a little cautious of the brake at first," said Held, "but then discovered that the hydrostatic drive system basically brings the machine to a smooth stop, and all you need is a light tap of the pedal. You don't come anywhere near pushing it to full stroke. But the operator should be mindful of the situation."

For the craning exercise, Held hooked on to a concrete manhole and made a lift over the 200W-7's deployed outrigger. He then extended the radius as he swung over the side. In his opinion, the outrigger and blade provided a stable platform for this maneuver. After a second lift over the end, this time on-rubber, Held traveled forward with the load to simulate a pick-and-carry situation.

"The machine seems to be a respectable lifter, and there's no problem with pick-and-carry, as long as the load is in front of you. I think that whatever you can pick, you can walk ahead with it."

In a final exercise, Held used the 200W-7 to dig on-rubber. We at first debated whether this was allowed, because the operator's manual did not specifically address this operating situation. But we concluded that on-rubber digging must be allowed, because the front axle's oscillation feature is locked out when either the service brake is fully depressed and latched or the parking brake applied.

Held was impressed with the machine's performance. It dug strongly in this configuration, he said, but he did caution that it's best to slow down when excavating on tires. He was especially impressed that when digging over the side, he could fully extend the 200W-7's boom and digging arm with a full bucket.

"That's a maneuver I couldn't do with the wheeled machine I ran for the contractor. Everything considered, I'd say the Hyundai is a very capable machine."

More like this

Comments on: "Rediscovering The Wheeled Excavator's Versatility"

Overlay Init