Cooling Tower Belts

V belts are commonly used between the motor and fan shaft on cooling towers. They have the advantage of allowing easy speed adjustment through judicious sheave selection, easy replacement and a forgiving nature for some misalignment.

The traditional belt for cooling towers is the 'B' section belt. 'A' belts are smaller and look like the ones you would find under the hood of your car 20 years ago. 'C' belts are quite large.

The basic V belt is uniformly 'V' shaped for its entire length. An improved design has notches that allow the belt to 'wrap' around the sheaves more easily. Notched belts are able to transmit more horse power particularly where sheaves are small in diameter as is the case with the driver sheave when an 1800rpm motor is made to turn a fan somewhere near 400rpm. If you're replacing notched belts, be sure the replacements are also notched. If you're replacing plain belts, the notched versions are always a better option.

Run your finger inside the 'V' groove on the driver sheave. If you feel any wear, the sheave needs to be replaced. Similarly, if the bottom of the 'V' groove is shiny, the sheave is worn out.

Don't confuse notched belts with cog belts. Cog belts lock the sheaves into a constant speed ratio and look like the typical automotive timing belt. Cog belts can transmit a lot of horsepower in a small package and are ideal for many applications but haven't worked too well for typical cooling towers. Cog belts require considerable tension and most cooling towers are rather flexible being constructed of sheet metal panels. By the time adequate tension is achieved, alignment can be way out of spec.