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Cooling Tower Motors

ABB’s Baldor-Reliance® RPM AC™ synchronous permanent magnet cooling tower motors use laminated finned frame construction to provide a highly efficient, power-dense, package with flange mounting dimensions that can replace the right-angle gearbox and jack shaft installation in many conventional cooling towers. This same technology is offered in conventional, yet power-dense, foot-mounted designs that can replace belt and sheave applications where more vertical mounting space is available. Derived from one of the toughest motor platforms used in the most demanding industrial applications, the RPM AC motor is proven to provide a high level of performance inside a cooling tower’s hot and humid environment.

Cooling Tower Motor Features

Increased efficiency and power factor performance

Operates at optimal system efficiency point with variable speed control

Increased system reliability with fewer mechanical parts

Simplified installation or retrofit with gearbox footprint

Inpro/Seal® combination slinger and labyrinth non-contact shaft seal protects motor from water ingress and contamination

Easy-to-use drive control parameters

Interfaces easily to building automation control systems

Replaces high-maintenance conventional gear and belt drive arrangements

Quieter operation than conventional motor/gearbox system

Common applications

Wet and dry cooling towers
Air cooled condensors
Air cooled heat exchangers

Common industries

HVAC
Chemical, oil and gas
Power generation

Conventional Cooling Tower Drive

Cooling Tower Motors and Controls

A cooling tower is a heat exchange system that removes waste heat from a process system fluid, usually water. Cooling towers are used in both commercial and industrial applications. The mechanical components of a cooling tower fan are made up of a motor, gearbox, drive shaft, disc couplings and fan impeller. The motor speed is typically 1,800 RPMs. Fan speeds are much slower and are determined by the diameter of the blades to keep the blade tip subsonic, typically around 90 to 230 RPMs. In cooler climates, the fans can be reversed to prevent freezing during the winter months. Average cells are 14 to 28 feet in diameter.

Improvements in system safety, reliability, efficiency and noise reduction are now possible with the introduction of new motor and drive technology applied to cooling tower applications. The same electric motor and control technology used to power today's most sophisticated hybrid vehicles has been adapted for cooling tower drive applications. Advances in motor power density using laminated steel frame construction combined with high flux strength permanent magnet salient pole rotor technology results in a high-torque, slow-speed, low-profile motor that is mounted directly to the fan and operates at an optimal speed to maximize system efficiency. The permanent magnet rotor construction also allows the motor to be manufactured in a compact form. The same basic motor design requirements for a hybrid vehicle of high torque, efficient, low weight, reliable, quiet and compact also apply to the cooling tower application.

ABB’s Baldor-Reliance RPM AC permanent magnet cooling tower motor with ACS880 variable frequency drive and +N5350 cooling tower drive controller are designed to drop directly into existing gearbox mounting patterns. A Retrofit can normally be accomplished in less than six hours. The greatest improvement to the fan drive efficiency is seen with the elimination of the gearbox from the system. Permanent magnet control greatly increases operating efficiencies even under lightly loaded conditions typical in fan applications at low speeds. Temperature rise in the motor is also considerably lower, making for a power-dense package with increased motor life over conventional induction motor systems.