In the ever-competitive aerial work platform business, manufacturers are always looking for subtle ways to gain a leg up. So when Genie Industries, Redmond, Wash., became the first OEM to unveil an electric boom lift, featuring a completely mobile, self-contained AC drive system, the industry couldn't help but take notice.
Although new to the access industry, AC drive systems are a proven technology, having been used in the industrial forklift market for many years. Their advantages include increased efficiency, faster speed, more precise maneuverability, and brushless motors.
The key to the AC drive systems' success is the ability to convert the conventional 48-volt DC power supply to a more efficient three-phase, AC current. While some efficiency is lost when inverting DC to AC, Genie's engineers explain that AC power is more efficient than DC because it draws the most precise amount of power to perform a task. Once converted, the AC current drives a pair of fully sealed, three-phase, brushless permanent magnet motors.
Meeting emission requirements
According to Phil Harvey, boom product manager for Genie, incorporating the AC drive concept on boom lifts has been in the works at his company for the last four
years, culminating in the introduction of its new 40-foot Z-40/23N and Z-40/23N RJ narrow electric articulating boom lifts at The Rental Show in February. (For an in-depth technical review of these two machines, see “Ground-Breaking Boom Lift” in the February 2007 issue of Lift and Access magazine.) Applying this configuration to a boom lift stemmed from a desire to keep up with evolving emission requirements, he says.
“About every two to three years, we need to redesign our engine packages because of emission requirements because they are more stringent in most of our worldwide markets,” Harvey adds. “Next year in North America, for instance, we're moving into Tier 3 for diesel machines and Tier 4 after that.”
With each tier comes added complexity and cost for the engine, says Harvey • a reality that's not going to change anytime soon. “Diesel engine prices are going to be going up with Tiers 3 and 4,” he says. “We're trying to look forward and see what we can do with an electric machine to make them feel like an internal combustion engine.”
Harvey says Genie could've gone the route of a traditional DC drive system, which it uses on its other boom lifts, but advancements in DC power control have somewhat slowed in comparison to AC systems. “Quite frankly, that would have been settling for five-year-old technology that's not really being actively improved,” he says.
AWP industry feedback
Targeting indoor plant maintenance customers who are looking for lighter weight machines, more maneuverability, and quiet operation, Genie has field tested the Z-40/23N and Z-40/23N RJ for the past four months, mostly in Midwestern plant and manufacturing settings. So far, feedback has been positive, and initial sales have been brisk, Harvey says.
From a customer perspective, it all comes down to performance, reliability, and cost. According to Harvey, customers are not necessarily basing their purchasing decision solely on the advantages of the new AC drive option but rather on what the machine can do. “I think they still just see this is an electric articulated boom,” he says. “They want more height, but as you get higher, the machines get heavier, making it harder to power them with traditional battery and electrical control systems.”
As an industry standard for industrial forklifts, AC drives have become more affordable for other industries, Harvey says. “It just seemed a natural thing to bring that over and apply it to aerial work platforms,” he adds. Without tipping Genie's hand, he says he's not sure how far the company will take the AC drive concept; however, it's going to be one technology to keep a close eye on.