Nc class stainless, Marley, Specifications: base – SPX Cooling Technologies SS-NC-08A User Manual

Page 7: Cooling tower

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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.

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