Baldor Extends Direct-Drive Solution To High Power Ratings For Power Generation and Large Processing Plants

Baldor has extended the range of its direct drive technology for controlling cooling tower fans to higher power ratings that can handle very large applications in power generating plants and heavy processing industries.

First introduced in 2009, Baldor's direct drive solution for cooling tower fans has eliminated the gearbox and right-angled coupling of conventional drive solutions to save energy, improve reliability, and run quieter.

The latest product additions now extend the power rating of the motors to delivers maximum torques of up to 13,500 Nm. In total there are now 26 choices of ratings available, spanning a drive power range from 7.5 kW at 500 RPM base speed to 187 kW at 130 RPM base speed, allowing optimum choices to be made for a very wide range of cooling applications from building HVAC (heating, ventilating, and air conditioning) systems to the large sizes of cooling tower fans used in many heavy-duty processing plants and power generating stations.

Baldor's solution, the VS1 Cooling Tower Drive, provides a direct slow-speed drive for the fans combined with variable speed control that is optimised for the building cooling application. By eliminating the drive shaft and gearbox the solution minimises moving parts, improving reliability and power efficiency - as well as reducing system bill-of-materials.

The interior permanent magnet synchronous motor design uses energy efficient technology that, in combination with the elimination of the gearbox and drive train transmission losses, results in a more efficient system compared to conventional fixed speed designs.

The direct drive fan motor is controlled by a Baldor VS1 drive with a specially developed speed control algorithm. Baldor's algorithm provides sensorless control of the permanent magnet motor that is optimised to manage the large inertia of the fan, with a low starting current requirement.

The motor is a synchronous type from Baldor's RPM family, based on permanent magnets. This produces a highly torque-dense motor, allowing Baldor to also offer the technology to the cooling tower retrofit market, for installation in the same space currently used for the gearbox. The motor will provide continuous constant torque over its entire range from zero up to base speed, and employs optimum pole construction to maximise both efficiency and power factor.

The drive system is now available in nominal power ratings from 7.5 to 187 kW (10 - 250 HP), 500 to 130 RPM base speed, to drive cooling fans from typically 2.1 to 8 metres (7 - 26 feet) in diameter.