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Specifications
Specification Value
Marley
/
Sigma 1000/1200 Cooling Tower
/
Specifications: Base
18
5.0 Mechanical Equipment:
5.1 Fan(s) shall be propeller-type, incorpo-
rating heavy duty blades of cast alumi-
num or high strength, inert composite
material. Blades shall be individually
adjustable and replaceable. Fan(s) shall
be driven through a rightangle, indus-
trial-duty, oil-lubricated, geared speed
reducer. Speed reducers employing
pulleys and belts will not be accepted.
5.2 Motor(s) shall be ____ hp maximum,
TEFC, 1.15 service factor, and specially
insulated for cooling tower duty. Speed
and electrical characteristics shall be
1800 (1800/900) RPM, single winding,
___ phase, ___ hertz, ___ volts.
5.3 Motor shall be located outside the fan
cylinder at the fan deck, and shall be
connected to the speed reducer by
a tubular stainless steel, dynamically
balanced driveshaft equipped with neo-
prene flexible coupling elements.
5.4 A galvanized oil gauge and drain line
shall extend from the gear reducer to
the vicinity of the motor, and shall be
equipped with a dip stick for oil level
measurement.
5.5 The complete mechanical equipment
assembly for each cell shall be sup-
ported by a rigid, unitized support that
resists misalignment between the
motor and the gear reducer. Support
shall be heavy-wall tubular steel, to
which heavy plate platforms for the
motor and gear reducer have been
welded and the assembly shall be hot-
dip galvanized after fabrication. The
support assembly shall also provide
an inlet connection for incoming hot
water, and shall serve as a crossover
pipe to deliver water to both sides of
the tower.
5.6 The mechanical equipment assembly
shall be warranted for no less than five
(5) years. This warranty shall cover the
fan(s), speed reducers, driveshafts and
couplings, and the unitized supports.
■ Standard fan drives of other manufacturers may use V-belts.
Considering the size of fans involved—and the horsepowers
applied—this is not good design practice. Geareducer
®
drive is
far more reliable and trouble free, and is currently offered as an
option by at least two other cooling tower manufacturers.
Unless otherwise specified, motor speed will be 1800 RPM in
60 Hertz areas and 1500 RPM in 50 Hertz areas. If you prefer the
operating flexibility of two-speed operation, please specify the
RPM to be 1800/900 (1500/750 in 50 Hertz regions).
The driveshaft turns at the motor speed and is, therefore, most
sensitive to operational imbalance. Stainless steel manufacture
assures that the driveshaft will not become unbalanced as a
result of corrosion.
The extended oil line to an external dip stick provides a conve-
nient means of checking the level of oil in the Geareducer. As
indicated on page 27, a sight glass is also available in lieu of the
dip stick.
Fans of the
size used on
large cooling
towers are
applied at
speeds and
horsepowers
that generate
considerable
torque—and
structural
tubular steel
resists this
torque very
effectively. The Marley torque-tube assures that all of the mechan-
ical equipment remains aligned, and that the rotating fan is prop-
erly positioned within the fan cylinder. Hot-dip galvanizing after
fabrication assures that all steel surfaces will be heavily coated
with zinc for long-term protection against corrosion.
Even in aggressive water conditions, the heavy construction of
the unitized support normally precludes the need for stainless
steel.
The value of a 5 year mechanical equipment warranty speaks for
itself. Except for the motor, all of the mechanical equipment on
a Marley tower is made by SPX Cooling Technologies. Cooling
tower vendors who purchase commercial fans, gear boxes,
driveshafts, etc. may require that you deal directly with those
commercial suppliers for warranty satisfaction.