By Pamela Winikoff

Founded in 1843 in Sugar Land, Texas, the Imperial Sugar Company has grown from a single plant manufacturing facility into the nation’s largest processor and marketer of refined sugar and allied sweetener products. Imperial o perates three sugar cane refineries and beat sugar factories, t wo molasses desugarnization facilities and over 30 food service, packaging, ingredient, warehouse, distribution and terminal facilities. With its sprawling facilities stretching from coast to coast, the company’s ability to reliably supply its customers is unmatched in the industry.

A year after Imperial Sugar began its operations, halfway across the country in Brooklyn, New York; Leviton Manufacturing opened its doors to produce mantle tips for the gas lighting industry. Before long, Leviton introduced a new product to meet the demands of a growing electrical industry–a pull-chain lampholder. Like Imperial, Leviton experienced dramatic growth through expansion, innovation and strategic acquisitions spanning nearly a century. Today Leviton stands as a leader in the electrical wiring device industry.

Leviton serves the needs of a broad array of industrial applications with rugged-duty connection, electrical safety, personnel protection, power quality, telecommunications and energy efficiency products. One of these power quality devices, the Lev-UPS Line-Interactive Uninterruptible Power Supply (UPS), produced a sweet outcome for Imperial’s Sugar Land processing operations.

21 st Century Automation Demands 21 st Century Solutions
Imperial’s Sugar Land facility generates its own electrical power using three co-generators that need to be synchronized with the local power company’s electricity. The facility is highly automated with programmable logic controllers (PLC’s) running 85% of its processing equipment. The PLC’s control everything from the plant’s filters and affinations to its presses, pallitizers and other heavy equipment. Like other sensitive electronic equipment, PLC’s are highly susceptible to surges, spikes, over voltages and other power disruptions and can malfunction or be destroyed outright when these events occur.

According to Albert Rosas, Imperial’s Electrical Instrument/Maintenance Forman Supervisor, “The power dips caused by the transfer of electricity from utility power to our own generating power were causing disturbances that were tripping the PLC’s. When the PLC’s registered the voltage irregularities, they would either shutdown or malfunction. We’d have to troubleshoot the situation and reprogram the settings on the PLC’s, all of which caused an interruption of service.”

The fact was that whenever power was shifted from the local utility to Imperial’s co-generators, the input voltage to the power supply cards on the PLC’s would drop from 120V to 90V or 95V for a period of 5–10 minutes. This would burn out the power supply cards at a replacement cost of $1500 per card. What was even more costly to Imperial was that the sugar processing equipment had to be shut down while the cards were being replaced.

Due to these frequent productivity losses, Mr. Rosas decided to investigate possible solutions to the problem. It was clear that a power-conditioning device was needed and the obvious choices were an AVR (Automatic Voltage Regulator) or a UPS (Uninterruptible Power Supply). Both devices can provide a constant voltage input to the PLC’s.

AVR vs. UPS
While an AVR would be a lower maintenance solution, it only offers voltage regulation, not back-up power. A UPS would not only provide the needed voltage regulation, but also power backup capability during momentary power interruptions. While these were not as frequent as the voltage drops, momentary interruptions were also having an adverse effect on Imperial’s PLC’s.

Line Interactive UPS
Provides Best Solution An assessment of the downtime and lost productivity was performed and the resulting analysis justified placing UPS devices in all of the critical PLC cabinets. Of the three UPS topologies available (Off-Line, Line-Interactive and On-Line), Imperial decided the ideal choice for its processing environment was the Line Interactive type. Off-Line Units provide no voltage regulation, a key requirement for Imperial, and would transfer power to and from the battery too often, reducing its life span. On-Line Units, while providing the best level of protection, tend to be less efficient and generate more heat than Off-Line and Line-Interactive types. This was a major consideration, given the units were located in a processing plant. A Line-Interactive unit provides the benefits of both the other topologies and includes automatic voltage regulation.

Lev-UPS
Provides Sweet Outcome Imperial selected Leviton’s Lev-UPS Catalog Number U0625-AKP Line-Interactive units rated at 625VA and installed them in various locations over a 6-month timeframe. The Leviton UPS devices feature Lev-CON Line-Interactive technology for battery back-up applications. Lev-CON’s line interactive voltage regulation compensates for minor sages and swells without transferring to the battery, extending battery service life. The devices also feature Lev-WARE™ UPS control and monitoring software as well as advanced battery management features. Once the Leviton UPS devices were installed, the power disruptions and downtime problems ceased. In fact, during a one-year period with the UPS devices installed, Imperial did not lose a single power card in their PLC’s. Imperial was so satisfied with the results that it not only retrofitted all of its PLC cabinets with these units, it also had a unit installed to provide a battery backup solution for its kronos clock.