Amcot ST Series - Page 8

AMCOT ST SERIES FIBERGLASS COOLING TOWER
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GENERAL OVERVIEW
TOWER CONSTRUCTION
Fan Blade Assembly
For ST Series models ST-3 thru ST-30 the fan assemblies are fixed pitch type, constructed from nylon.
The pitch angles are preset by the factory to ensure proper operation and maximum allowable air flow is
being generated while maintaining proper motor amp draw.
For models ST-40 and ST-50 the fan assemblies remain fixed pitch, but the fan blades are constructed
from aluminum alloy while the hub is nylon.
For ST-60 through ST-1500 fans are adjustable pitch type and constructed from light weight corrosion
resistant aluminum alloy. Blades are secured to the fan hub through a serious of stainless steel U-bolts.
Adjustable pitch fans do allow for some minor adjustment on the customer’s part when it comes to air
flow through the unit, however it is not recommended that you make these adjustments unless you are
a licensed professional.
WARNING: Failure to properly balance fan assemblies can cause equipment failure, excessive
vibrations, and personal injury in the event of a failure. It is critical that fans be balanced prior to
startup by the installing technician even on towers that shipped preassembled!
Fan Motors & Reducers
Amcot ST Series models ST-H-5 thru ST-200 are supplied with direct drive motors which means that the
mechanical assembly simply consists of a motor and fan assembly. For these units, there are no
bearings to grease or belts to adjust.
On models ST-225 thru ST-1500 the mechanical assembly incorporates a housed belt reducer which
regulates the output speed on the fan assembly to ensure proper air flow is maintained while
minimizing sound generation. The reducer assembly is fully housed in an epoxy coated steel case with
removable side walls for accessing the internal components and for adjusting belt tension. For
adjustment and maintenance please see the appropriate section of this manual for more information.
Motors on the Amcot towers are designed to meet NEMA energy requirements and are UL/CSA
approved and are IP55 compliant. On models ST-30 thru ST-1500 the motors can be operated on
variable frequency drives (supplied separately) in order to maximize energy savings. In addition, all
motors can be operated on standard on/off type of temperature controllers (sold separately).
Models ST-H-5 thru ST-H-20 utilize single phase 110/220v dual voltage motors which can accommodate
either service power. ST-H-20 also has the ability to be supplied with a three phase 208-230/460v multi-
voltage motor. ST-30 thru ST-1500 are supplied in 3 phase 208-230/460v motors as a standard. For
special motor voltage requirements, Amcot can provide such motors which would be special order and
have extended lead times.