Cummins celebrates long-term partnership with the Navajo Nation as it supplies reliable power to resort

Cummins was entrusted to supply a premier destination resort in a rural location with emergency standby power. The Twin Arrows Navajo Casino Resort, located about 25 miles east of Flagstaff, is a 267,000-square foot property that showcases the Navajo culture with original artworks throughout the resort. Twin Arrows is owned and operated by the Navajo Nation Gaming Enterprise (NNGE).

A flagship property of the NNGE, the resort was designed to honor the Navajo heritage. Like a hogan—a traditional Navajo home—the entrance faces east and the largest windows face north to the sacred San Francisco Peaks. The property includes more than 1,000 slot machines, a conference center, indoor pool and several restaurants in addition to a five-story hotel with 90 rooms.
 
The Navajo Tribal Utility Authority (NTUA) and the NNGE turned to Cummins exclusively for this project, based on the performance on prior Navajo casino projects and our ability to meet the customer’s needs. Twin Arrows Casino is the fourth Navajo tribal casino project for which Cummins Power Generation has supplied generator sets and equipment—three others are in New Mexico. 

“Reliable backup power is very critical for us as a gaming facility. In our experience with the Cummins systems that we have at our other properties, we didn’t hesitate to have the Cummins equipment speced out at Twin Arrows,” said Jim Wanamaker, Facilities Manager for NNGE. “For us, life safety is always of the utmost importance. Beyond that, the critical need for us as a gaming operation is that we don’t lose power to the gaming floor or the gaming slot systems to maintain play on the floor. Security systems are also critical: if security goes down, we have to shut down the gaming systems as well.”

The Cummins system included two low-voltage (480V) generator sets at 2 MW each. In addition, a Cummins PowerCommand® DMC 300 paralleling system and nine sections of switchgear were designed to directly interface with the PowerCommand controls on the Cummins generators. Each generator includes a 24-hour base tank and is encased in a sound attenuated enclosure.

Closed-transition design eliminates harmful back-feeding

“The generators are set up as a prioritized system so that the emergency systems take the highest priority. The second priority is the legally required standby and business-critical equipment,” said Leslie Fernandez, senior electrical engineer with Las Vegas-based JBA Consulting Engineers.

“We minimized the adverse effects of transferring power from the generators to the utility with a closed-transition system with soft loading capability through the Cummins’ paralleling switchgear which is designed to control the generators so there’s only insignificant back-feeding of generator power to the utility distribution system,” Fernandez said. 

In the case of power disruptions or unstable power supply involving business-critical operations, the first line of defense at Twin Arrows are three uninterruptible power supply (UPS) backup units. The battery-powered units maintain power to key casino operations that include surveillance and security systems, gaming slot and player management systems as well as emergency lighting, HVAC and other systems. “The UPS systems bridge the approximate 10-second gap between when normal power goes out and the shift to the Cummins generators,” Wanamaker said. 

Swift support in a rural location

The Cummins system ensures a reliable power supply at Twin Arrows, Wanamaker said, which is particularly critical in a rural, desert location prone to outages due to weather. 

Following delivery of the Cummins switchgear and generators to the job site, the switchgear was commissioned onsite. Performance testing and final validation testing of the load bank on the generators were performed in late September 2012. Full commissioning of the system was completed in late January 2013 in preparation for the resort’s May 2013 grand opening. 

“The performance of the Cummins equipment, both the transfer switches and the generators, has been exceptional to date,” Wanamaker of NNGE said. “More than that, the service we received from Cummins Rocky Mountain was excellent. They responded immediately to us with a recent power outage incident and were available on site within less than two and a half hours.”

"The performance of the Cummins equipment, both the transfer switches and the generators, has been exceptional to date." — Jim Wanamaker, Facilities Manager Navajo Nation Gaming Enterprise Properties

For more information about Cummins Power Generation systems, contact your local Cummins Power Generation distributor at power.cummins.com.

This case study is dedicated in memory of long-time Cummins customer Reevis Begay (1960-2012) of the Navajo Tribal Utility Authority.