10
installation
When using a VFD:
Before beginning, ensure that the motor is rated for “Inverter Duty”
per NEMA MG-1, part 31.
• Set the VFD solid state overload protection to 119% of motor nameplate
amps and set “maximum current parameter” in the VFD to motor nameplate
amps. “Maximum current parameter” will reduce fan speed and limit amp
draw to nameplate amps during cold weather operation. If furnished with
a mechanical O.L. set this at 110% over motor nameplate amps.
• Motor rotation must be the same in both VFD mode and By-pass mode.
• 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.
• 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 Cool-
Note
Warning
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