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Established in 1988, the mission of the University of Hawaii at Manoa’s School of Ocean and Earth Science and Technology (SOEST) is to make the center a leading institute in ocean and earth science and technology. SOEST scientists and engineers work to understand the interrelationships of the sea, atmosphere and Earth to learn how to sustainably enhance the quality of our lives, as well as bring an enrichment of intellect, culture and technological advances to Hawaii.
Read why the university deployed an Eaton 93PM UPS to protect its deep-sea remotely operated vehicle.
The unique application requiring power protection is “Luʻukai,” a remotely operated vehicle (ROV) that is an integral part of SOEST’s Ocean Technology Group (OTG), which is located at the University of Hawaii Marine Center. Translated to “Sea Diver,” the two-part system ── consisting of the vehicle that performs science operations on the seabed or in the water column and a tether management system (TMS) that hovers above the working vehicle ── relays high-definition video and other data to and from the support ship on the surface. Capable of diving 19,600 feet, the 3,200-pound ROV enables researchers to sample and collect data from abyssal to shallow coastal and seamount waters.
“We’re the tool the oceanographers use to study different ecosystems deep down in the ocean,” explains Blue Eisen, a marine research engineer with SOEST.
Although the system was designed to run off the ship’s power, doing so was causing significant issues with Luʻukai. “When we do operations, we use dynamic positioning with GPS and a bow thruster to hold our position over the work site,” Eisen says. “The demand on power is highly variable so the voltage fluctuates dramatically, which can damage our equipment.
To address the power quality issues on board, the OTG initially rented a large commercial generator each time Luʻukai was operating. Yet considering the fact that the deep-sea robot is launched on up to 60 outings per year, this option proved both expensive and inconvenient. SOEST desired an economical solution that would deliver continuous, clean power to the ROV and eliminate the need for the generator rental.
“The problem with relying on the ship’s power is that the voltage fluctuates frequently.”
Based on a recommendation from the ROV’s manufacturer, in 2021 SOEST decided to bring a new captain on board: the Eaton 93PM UPS. Preventing harmful voltage fluctuations from reaching Luʻukai, the UPS has successfully kept the ROV’s operations in ship-shape ever since.
Combining efficiency and reliability in a space-saving, scalable design, the 50 kW 93PM UPS shields the highly sensitive robotic equipment against damaging power anomalies. “We use the Eaton system as a power conditioner,” Eisen explains. “One moment, the ship might be receiving 480V power and another moment it could be 470V power. If our ROV system was to receive a 10V fluctuation, that would be a real problem. The UPS allows us to run on ship’s power and not be affected by these voltage variations.”
“The Eaton UPS gives us stable 480V power regardless of what the ship is doing, with the battery providing a buffer. It also gives us enough time to shut down our systems in a safe way if the ship experiences any power generation issues.”
The unit not only protects against changes in voltage, but also allows operators to safely shut down equipment in the event the ship loses power completely. “That 15 minutes of battery gives us the time we need to do a smooth, controlled shutdown,” Eisen says. “As opposed to the ROV being in the middle of holding onto a rock with a hydraulic clamp and then everything just goes black.”
The 93PM affords easy management with a friendly, graphical LCD touchscreen interface that enables users to view system status from a distance with green, yellow and red LED light bars, as well as track statistics on battery time and load profiles.
SOEST also appreciates the unit’s compact footprint, which slips easily into one of two 20-foot shipping containers used to house and transport the ROV and its related equipment, including a control van, power distribution system and underwater navigation.
“The 93PM was a very cost-efficient solution. The unit will pay for itself within two years from generator rental savings alone.”
Even more, with its ability to accommodate 50Hz power, the 93PM fits well into the school’s future plans ── with Luʻukai set to explore oceans beyond the U.S. “The fact that the 93PM can accept 50Hz is yet another benefit,” Eisen confirms. “This will enable us to make that conversion if we take the ROV on a European ship, which we plan to do in the future.”
Startup on the 93PM was completed by the Eaton UPS services team, which Eisen reports went extremely well.
“They made a few little adjustments in about 10 minutes, which would have taken us days to figure out,” he acknowledges.
“The first couple of years we had problems with the ship’s power, with voltage changes causing all kinds of issues with our electronics. The Eaton unit has bypassed all of that.”
