The cooling tower application presents a unique dilemma for
the customer or user. Larger cooling tower assemblies are
made up of multiple motor, gearbox, and cooling fan assemblies,
collectively viewed and treated as a mass produced
product consisting of several identical drive systems. The
focus of this investigation is primarily on the larger multiple
fan systems that employ double reduction enclosed gear
drives to reduce motor speed to fan speed such as those
found in power plants and refineries. These gear drives
typically consist of a first reduction bevel gear set and a
second reduction parallel shaft gear set. This gear drive
configuration transmits motor power from a horizontally
oriented motor to a vertically oriented fan shaft. However,
many of the concepts and ideas discussed are also
applicable to single reduction cooling tower enclosed
gear drives consisting of a single reduction bevel gear set
that transmits motor power from a horizontally oriented
motor directly to a vertically oriented fan shaft.
The cooling tower application is demanding and often
requires unique component capabilities to meet a variety
of environmental and operational challenges. As a result, the
supplier’s purchasing function will often pursue a low cost
quick fix product solution, which is in direct contrast with
the users’ or customers’ need for a reliable long-term solution.