Nearly a decade ago, Baldor Electric Co. set out to simplify and redesign the ubiquitous right-angle gearboxes widely used in industry to transmit power to cooling tower fans. But a funny thing happened on the way to a new gearbox design, according to Roman Wajda: The gearbox was eliminated altogether in favor of an innovative direct motor drive solution that achieved significant gains in energy efficiency and dramatically improved reliability.
"We began evaluating the cooling tower industry in July 2005 regarding a new gearbox solution that would achieve better sealing, lower maintenance and higher reliability," explained Wajda, industry business manager for Baldor, now a member of the ABB Group. "But industry’s response to this plan was lukewarm because gearboxes historically had a lot of problems with oil leaks, environmental contaminations, high maintenance and low reliability. They wanted to remove these problematic components." To satisfy this objective, Baldor designed a permanent magnet motor that could provide the necessary torque, yet fit directly into the space formerly occupied by the gearbox. Wajda described the continued success of Baldor's Cooling Tower Intiative (CTI) at a presentation this week at ABB Automation and Power World in Orlando, Fla.
To develop its solution, Baldor and its CTI initiative focused on three main areas: permanent magnet motor technology; finned frame designs that could remove enough heat to allow 25% more power density; and higher-performance insulation methods. Baldor first presented its electrically driven, variable-speed motor solution to OEMs in July 2007 and installed its first beta test as a retrofit to an existing cooling tower at Clemson University in June 2008. Installation test data showed that the new solution boosted overall electrical efficiency by 11%, as well as reducing noise by 5 decibels (dB). "For reference, a reduction of just 3 dB cuts what the human ear can hear by half," said Wajda.
Because of these performance advantages, some 400 cooling towers have been equipped or retrofitted with this solution for companies ranging from NL Pharmaceutical in Denmark to Cargill in Turkey to Intel in California. "CTI's ultimate goal is simplicity and low maintenance, but we're still in the early stages in many ways," said Wajda. "Industry is still often slow to change from the inefficient technologies of the past. But, once we get that first one installed, they're convinced."