SPX Cooling Technologies Cooling Tower Marley MD - Manual (Page 10)

10
Installation
• If cable distance between the VFD and motor is greater than 100
feet a DV/DT output filter is recommended to avoid damage to the
motor. 100 feet distance is based on our field experience, the VFD
manufacture may state different distances and distance does vary
depending on the VFD manufacture.
• Program the VFD for variable torque output. Flux vector and con-
stant torque modes may damage the gearbox.
• Do not start and stop the motor using the safety switch at the motor.
If the drive is being commanded to run and the load side is cycled
ON and OFF with the safety switch this may damage the VFD.
Using a VFD in cooling applications has advantages over traditional
single or two speed motor control. A VFD can reduce the cost of electrical
energy being used and provide better temperature control. In addition, it
reduces the mechanical and electrical stress on the motor and mechanical
equipment. Electrical savings can be large during periods of low ambient
temperature when the cooling requirement can be satisfied at reduced
speeds. To benefit from these advantages, it is important that the drive be
installed correctly.
Marley supplies VFD and VFD controls specifically designed for our cooling
products. If you have purchased a Marley VFD and/or controls package,
please follow the instructions in the User Manual for that system. Most
VFD problems can be avoided by purchasing the Marley drive system. If
you are installing a VFD other than the Marley drive, please refer to that
drives installation manual.
Improper use of a VFD may cause damage to equipment or personal
injury. Failure to correctly install the VFD drive will automatically void
all warranties associated with the motor and any equipment that is
either electrically or mechanically (directly) attached to the VFD drive
system. The length of this warranty avoidance will be contingent on
properly installing the VFD system and repairing any damage that may
have occurred during its operation. SPX Cooling Technologies does
not assume responsibility for any technical support or damages for
problems associate with non-Marley brand VFD systems.
Changing the operational fan speed from the factory settings could
cause the fan to operate in an unstable region which may result in
damage to the equipment and possible injury.
Warning