Dynamic Defense Environment Adopts Flexibility in Air Handling Applications

New Reliance flexible motor/drive product from Baldor saves installation time and cost for Raytheon Systems Company

Lower life cycle costs. Today's magical term for using the best products for an application, at the lowest cost and for the longest time possible. For automation applications, lower life cycle costs can be as simple as buying product that requires simpler wiring, or shares similar communication protocols. Finding lower life cycle costs also can require complicated research into products packed with features ear-marked for future use, or with an unsurpassed maintenance reputation. While there's no magic in understanding that investing in quality products and practices saves money long-term, for some companies, the magic lies in defining long-term application needs.

One such example is Raytheon Systems Company (RSC) in Dallas, Texas. The builder of defense equipment recently worked with Texas Air Systems, Irving, Texas, to find a new way to keep an air handling unit flexible enough to adapt to changing manufacturing room requirements. The result was the installation of the Reliance VSM 500™, a three-phase variable speed AC motor/drive product that makes variable speed control more affordable without sacrificing ease of installation and reliability.

Manufacturing Commands HVAC System Changes

Housed in a 40-year-old building on the Dallas campus of Texas Instruments, RSC's three-story, 1.3 million square-foot building contains manufacturing, testing and clean room facilities with all structural and industrial piping needed to support and run the building.

When it comes to caring for the facility's heating, ventilating and air conditioning (HVAC) system, managing life cycle costs at Raytheon can be challenging. Each of the building's manufacturing rooms is dynamic, with manufacturing specifications that may change as often as every other year. The changes naturally present a number of challenges - such as whether the 'new' manufacturing room must meet humidity and temperature requirements, or if structural modifications such as sound-proof walls must be made. But in addition, Raytheon's life cycle challenge is to facilitate changes in the HVAC system with flexible, reliable equipment.

Arming for a Dynamic Defense Environment

The air handling system at Raytheon's Dallas facility includes 400 air handling units and 17 fresh air fans that supply all air conditioning, air quality, and humidity control to the company's office and manufacturing rooms. Separate air handling systems satisfy the building's clean room requirements.

"It's natural for us to spend time on air handling maintenance for a building of this age," said Don Rutherford, SC building maintenance manager, Raytheon Ssytems Company. "But with all the other maintenance needs of the building, we have to be careful about how we manage our time installing equipment or maintaining units."

Raytheon has a long-term working relationship with Texas Air Systems, Irving, Texas, to research and develop new ways to simplify maintenance at the Dallas facility. They recently worked with Texas Air Systems, to expand flexibility on one of the air handling units - air handler 1418 (AH1418). AH 1418 is used to maintain a temperature of 72 degrees for a 1,200 sq.-ft portion of the manufacturing floor. Running 24 hours, AH1418 was driven by a single motor which lacked the flexibility for any change in air speed. To expand flexibility, Texas Air Systems recommended the Reliance VSM 500, a three-phase variable speed AC motor/drive product from Baldor.

"With our stand-alone motor, changes in speed meant re-adjusting internal components of the motor, or simply swapping the motor for one with the desired speed capabilities," said Rutherford. "The VSM 500 motor/drive combination gives us the variable speed drive technology in one package - without having to install anything additional."

Single Product Installation Saves Time and Cost

Because Rutherford and his maintenance staff already devote a significant amount of time to maintaining the building's air handling system, simple installation of any new product, including the VSM 500, is key.

"In most cases when a new motor is installed, we either build a separate stand next to the motor to wire a remote readout, house the drive in a nearby cabinet, or simply, forgo the variable speed option and just install a motor," said Rutherford. "The VSM 500 installed just like a motor, saving us the time and cost of extra wiring."

Rutherford also said the integrated drive and motor helped eliminate the need for an electronic disconnect, and results in better lead lengths. Simple built-in set-up parameters inherent in the VSM 500 also help reduce equipment costs. In fact, a user installing a VSM will pay as much as 20 to 40 percent or $200 - $1,000 less for the features of the integrated product verses buying a separate motor and drive with comparable features for an application.

"Because our older system runs the risk of shutting down, especially at night, one of the features we rely on is automatic re-start," explained Rutherford. "The re-start feature allows the VSM 500 to automatically start running again, in sync with the control system and without the need for any hands-on maintenance."

Leveraging Inherent Features for Future Use

From the beginning of any project, Raytheon is mindful of its dynamic environment and looks for ways to maintain flexibility. Currently, critical components of the air handling system are linked to the building's control system, allowing technicians to view the status of any unit's motor or drive, and to change speeds as necessary. Others are linked to pressure sensors or dampers, which report back to individual drives on needed air speed increases or decreases, or air volume changes.

"Our air handling needs are full of variables," said Rutherford. "In any particular room we may need to control air speed, volume and temperature. These variables may be controlled by sensors, dampers or a variable speed drive. We're not yet using all of the functionality of the VSM 500, but knowing we can adjust to any given situation makes us more competitive."

Reliance is a registered trademark of Baldor. VSM 500 is a trademark of Baldor.

Reprinted with permission from Air Conditioning, Heating & Refrigeration News, October 1998.