When using a cooling tower, the size of the sheaves (or pulleys) will determine the speed; the different size of belts will provide the speed reduction needed. The smaller sheave connects to the motor, while the larger fan sheave is attached to a fan shaft. The ratio between the two sizes dictates the decreased speed. The cooling tower fan belts that equal the profile and length requirements of the sheaves that transmit power. Different from gears, belt drives are open to the cooling tower’s moist, heated conditions. At first the cost of a belt drive is low, but maintenance upkeep costs usually grow over time. Sheaves and other components can corrode; and over time belts will stretch and lose their tension. Starting at around 95 % efficiency, over time the belt drives can reach the low 90 percentage or possibly lower as the belts lengthen and wear. Maintenance usually includes replacing the belt regularly and fan shaft bearing lubrication is needed a number of times a year, adding to its higher lifetime cost to operate. Quarterly sheave alignment checks are also recommended. The lifetime and dependability of a belt drive system usually depends on the care and attention they receive during their life. Belt drives are often used in cooling towers with low horsepower requirements.

• Belts Should Be Checked Monthly
• Belt Tension Should Be Adjusted Quarterly
• Belt Must Be Replaced Periodically
• Pony Motor Is Recommended For Redundancy In Single Tower Applications To Avoid Tower Downtime
• Not Available For Fans Above 75 Horsepower
• Better Ease Of Service And Lower Maintenance Cost That Gear Driven Devices