In some cooling tower applications, direct drives are capable of achieving a one-to-two percent efficiency advantage compared to gear drive systems. Efficiency can also be equal to or less than a gear drive system . To meet the torque requirements for cooling towers, permanent magnet motors become heavier and taller than standard induction motors. Maintenance professionals must possess knowledge of permanent magnet technology due to its potential to generate electricity even when the power is shut off. A VFD is required to control speed and conserve energy.
Direct drive permanent magnet motors are a newer technology available on most Marley NC Cooling Towers. The permanent magnet motor directly drives the fan, eliminating a number of components, including the gear drive, driveshaft, pillow block bearings and couplings, and associated installation and alignment costs. Compared to other power transmission technologies, direct drive motors can have significantly higher initial costs. However, customers can realize substantial savings on annual energy and maintenance costs.
- Designed for outdoor duty to handle the extremes of 100% humidity
- Prevents water ingress along the shaft
- Motors are available with either foot or flange mount designs
- High performance paint system and synthetic grease
- Bearing lifetime exceeding L-10 100,000 hours for increased reliability
- For new or retrofit industrial cooling systems up to 650 rpm / 11,000 Nm
- Vibration pad standard for FL58XX frame motors and optional on smaller motors
- Thermostats are standard on all motors. Their connection is required to validate the motor’s warranty.
- Winding stator RTDs are standard on FL58XX frame motors and optional for smaller motors
- Water ingress along the shaft is prevented with the slinger over Inpro seal for FL44XX and FL58XX and with V-ring slinger on smaller motors
- Multiple bolt circles on the N-end shield for easy replacement installations
Advantages of Direct Drive Motor
- Eliminate the need for gearbox, gearbox cooling system, driveshaft, couplings and bearings. This reduces maintenance and offers improved reliability.
- Reduce maintenance up to 90% . The direct drive motor could result in up to 90% or more less maintenance, depending on retrofit
- Lower vibration and system noise. The direct drive motor results in 5 dB(A) or more noise reduction in operation, depending on retrofit
- Save energy and eliminate startup current peaks and stresses from across-the-line startup
- Increase safety due to removal of rotating equipment