What are the advantages and disadvantages of belt drive vs direct drive fans?
The decision as to whether to use direct or belt drive fans hinges mostly on how the fan will be used, which often comes down to fan size. Direct drive fans generally cost less to buy, require less maintenance, and have less performance variance than belt drive fans. Belt drive fans are more efficient for given airflow capacity, and are quieter. These differences mean that direct drive fans are used more often in smaller sizes for mixing or minimum ventilation, and belt drive for larger fans used in tunnel ventilation. For the on-off, low-volume use involved in minimum ventilation, a rugged, low maintenance, and long life fan is needed, and efficiency and maximum airflow capability may not be the main considerations. For tunnel ventilation, on the other hand, where fans are called on to move a lot of air on almost a continuous basis, the fan must be larger and more efficient, to keep the electric bills down. In this situation, the belt drive is usually the best choice. A crucial point
