UPS at the Heart of Aircraft Manufacturer Downtime Mystery

Oct. 21, 2013
An unexpected machine stoppage resulted in the scrapping of thousands of dollars worth of expensive airplane parts. Experience from a previous job helped one CNC engineer troubleshoot the problem.

The innovations behind general aviation may have begun with the Wright brothers—two likeminded young men who built and controlled the world’s first successful human flight—but before their success could be attained, a bit of trial and error was required. The two studied the workings of bicycles and printing machinery to learn how to propel their ambitions. Such is the case for all entrepreneurs, including the engineering staff of one of the world’s leading general aviation manufacturers.  When unscheduled downtime occurred on their aircraft assembly line, it took some trial and error to diagnose the problem.

In the civilian aircraft industry, only a few manufacturers actually supply the market, primarily due to the high-level of technology and stringent manufacturing and safety standards demanded by the Federal Aviation Administration (FAA), Department of Transportation (DOT) and other governmental agencies. The systems creating and assembling an aircraft’s lightweight composite materials and sophisticated electronics are an amalgam of technology, chemistry, cutting edge equipment and quality assurance.

The manufacturing floor for this company is a literal maze, incorporating networked computers, PLCs, robots and other power-sensitive electronics that must operate reliably from the same utility power as that supplying motors, heavy machinery or welding processes. These aggressive applications generate high levels of localized power pollution, and can be the source of problems for more power-sensitive equipment. It was in this maze of power-hungry technology that this aircraft manufacturer had to assure uninterrupted process control.

In an initial attempt to address power problems, the company’s engineering staff made the decision to implement an uninterruptible power supply (UPS) to safeguard day-to-day operations. That was a good move. But they made the common mistake of thinking all UPSs are equal. This became very clear when an unexpected machine stoppage resulted in the scrapping of thousands of dollars worth of parts.

Due to the high cost of the scrap, the engineers began searching for the culprit. As with many troubleshooting tasks, the problem was not initially obvious. But soon CNC engineer Rob Ayala discovered that “the microcontroller responsible for monitoring a key stage in the parts manufacturing process was being subjected to transients and dirty utility power. This would frequently result in the loss of critical data communications, requiring the process to be shut down prior to completion.”

Solving process problems
Having spent over two decades in the aerospace industry, Ayala started out in a technical support role at another major civil aviation company and it was there he became familiar with the different UPS topologies. “There, we had solved a process power problem by deploying online UPSs in a particular cell, replacing line-interactive UPSs,” he says. Turns out his new company was using a line-interactive UPS too.

“We determined that the line-interactive UPS that we expected would be protecting our sophisticated manufacturing system only provided basic battery backup and minimal power conditioning,” Ayala said.

In his previous support role, Ayala would frequently receive calls about malfunctioning line-interactive UPSs. “It was almost always the result of weak or dead batteries that had failed prematurely,” he says. “In some of these cases we discovered the batteries had swelled up inside the UPS, making them impossible to replace. We then had to scrap the entire unit.” 

The line-interactive UPS was designed to protect computers in a home or office from power outages. It just wasn’t rugged enough for a manufacturing environment. In fact, “we moved the line-interactive UPSs to backup non-critical computers and, as time passed, we noticed a difference: The batteries inside the online UPSs would last for several years—typically two to three times longer than the one- to two-year life we would get from the line-interactive systems,” Ayala says.

Faced, at his new plant, a revenue drain from costly scrap due to a line-interactive UPS, Ayala decided to employ his knowledge of UPS design topologies. “A true online topology UPS regenerates new, continuous, clean AC power. This process eliminates a much wider spectrum of power quality problems, maintaining the optimum power levels demanded by the equipment,” he explains.

“When I went to the Internet to research online UPSs, I initially selected the manufacturer I previously used,” Ayala says. I wasn’t impressed with the website or the product selection, and decided to look at other brands that might be more rugged.

Ayala found Falcon Electric ( says he was impressed with its website, and sales and technical staff. He chose Falcon’s SSG Industrial-Grade High Temperature Rated Online UPS models, which “proved to be ideal. They are specifically designed for industrial applications in environments with temperatures up to 55°C.” He ordered several of the SSG 1.5kVA units. 

“After installing the UPS we haven’t lost a single production run,” Ayala says. “We have been using the SSG units for protecting our critical manufacturing processes for over three years now without any problems.”

“Ayala adds,“It’s clear that as more and more microprocessor-based equipment finds its way to the production floor, an industrial-grade online UPS is the right power solution to ensure reliable operations."

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