Filter
Top Products
Specifications
Specification Value
Marley
/
NC Class Stainless Cooling Tower
/
Specifications: Base
7
5.3* The tower shall include all design and
material modifications necessary to
meet the fire rating requirements of
Factory Mutual. The product proposed
shall be listed in the FM Approval
Guide, latest edition.
*Standard on models NC8301 thru NC8309. Available
as an option on models NC8310 thru NC8312.
6.0 Mechanical Equipment:
6.1 Fan(s) shall be propeller-type, incor-
porating wide-chord aluminum alloy
blades and galvanized hubs. Blades
shall be individually adjustable.
Maximum fan tip speed shall be 66
m/s. Fan(s) shall be driven through a
right angle, industrial duty, oil lubricat-
ed, geared speed reducer that requires
no oil changes for the first five (5)
years of operation. The gearbox bear-
ings shall be rated at an L
10A
service
life of 100,000 hours or greater.
6.1 (alternate)* Fan(s) shall be propeller-
type, incorporating wide-chord alumi-
num alloy blades and galvanized hubs.
Blades shall be individually adjustable.
Fan(s) shall be driven through a one-
piece multi-groove, solid back V-type
belt, pulleys, and tapered roller bear-
ings. Bearings shall be rated at an L
10A
service life of 40,000 hours or greater.
*Currently available on Models NC8304 through
NC8309.
6.2 Motor(s) shall be ____ kW maximum,
TEFC, 1.15 service factor, variable
torque, and specially insulated for cool-
ing tower duty. Speed and electrical
characteristics shall be ______ RPM,
single-winding, ___ phase, ____ hertz,
____ volts. Motor shall operate in the
shaft-horizontal position, and name-
plate kilowatt shall not be exceeded at
design operation.
6.3 The complete mechanical equipment
assembly for each cell shall be support-
ed by a rigid steel structural support
that resists misalignment between the
motor and the gear reducer.
■ The Marley NC is the only crossflow
cooling tower approved for single-cell
FM installations. This could have a very
beneficial effect upon your fire insurance
premiums. Towers not able to meet FM
requirements may require the inclusion
of a fire protection sprinkler system to
achieve a comparable level of insur-
ance premium cost. Even if you are not
insured by FM, this requirement ensures that each cell will contain any
fire that may occur without losing the ability of limited operations and
capacity.
■ Propeller-type fans require only half the operating hp of blower-type
fans. However, they should be readily adjustable to permit compensa-
tion for jobsite conditions.
With NC, the choice is yours. The exclusive Marley System5
Geareducer
®
requires no oil changes for five years, offering you
unmatched reliability and low maintenance. Ideal for owners concerned
about downtime or maintenance costs. Currently available on 49 NC
models, the Marley Power Belt drive system features all-aluminum
sheaves, power band belts and long-life bearings for dependable ser-
vice.
TEFC motors offer additional benefits over TEAO motors whose only
source of cooling is the flow of air produced by the cooling tower fan.
This air rate is not always ideal due to motor position, blockage, etc.
TEFC ensures the motor will always be cooled properly.
Unless otherwise specified, motor speed will be 1500 RPM on standard
models. Low noise models will use motor speeds appropriate for the
specific model. If you prefer the operating flexibility of two-speed oper-
ation, please specify two-speed, single-winding motors which offer full
and half speeds for maximum energy savings. Incidentally, two speed
motors are a better choice than separate “pony” motors which simply
double the problems indicated above and induce parasitic loads during
operation for lower than nameplate efficiency.