SPX Cooling Technologies SS-NC-08A specifications Specifications, Specification Value

Marley / NC Class Stainless CoolingTower / Specifications: Options 16

Specifications Specification Value

in quantities and locations as indicated on the drawings. An overflow and drain connection shall be provided in each cell of the cooling tower. The basin floor shall slope toward the drain to allow complete flush out of debris and silt which may accumulate. Towers of more than one cell shall include stain- less steel flumes for flow and equal- ization between cells. The basin shall be accessible and maintainable while water is circulating.

Fan Motor Variable Speed Drive:

Marley All Weather ACH550 System

6.4Add the following paragraph in the Mechanical Equipment section when VFD is used with customers Building Management System: A complete UL listed Variable Speed Drive system in a IP10 indoor, IP52 indoor or IP14 outdoor enclosure shall be provided. The VFD shall use PWM technology with IGBT switching and integrated bypass design. VFD out put switching shall not cause mechanical issues with gearbox teeth or drive shafts. The VFD shall catch a fan spinning in the reverse direction without tripping. The panel shall include a main disconnect with short circuit protection and external operating handle, lockable in the off position for safety. The VFD system shall receive a speed reference signal from the Building Management System monitoring the tower cold-water temperature. As an option to receiving the speed reference signal from a build- ing management system, the drive must have the capability to receive a 4-20 ma temperature signal from an RTD trans- mitter. The VFD shall have an internal PI regulator to modulate fan speed main- taining set point temperature. The drive's panel display shall be able to display the set-point temperature and cold-water temperature on two separate lines. The bypass shall include a complete mag- netic bypass circuit and with capability to isolate the VFD when in the bypass mode. Transfer to the bypass mode shall be manual in the event of VFD failure. Once the motor is transferred to the by-pass circuit the fan motor will run at constant full speed. The bypass circuit will not modulate ON and OFF based on

■Marley Variable Speed Drive systems are designed to combine absolute temperature control with ideal energy management. The cooling tower user selects a cold water temperature and the drive system will vary the fan speed to maintain that temperature. Precise temperature control is accomplished with far less stress to the mechanical equipment compo- nents. The improved energy management provides fast payback to the user.