FloAire Demand Control Ventilation System - Manual (Page 10)

A0023662
May 2014 Rev.5
10
Variable Frequency Drive (VFD) Installation Instructions
Input AC Power
1. Circuit breakers feeding the VFDs are recommended to be thermal-magnetic and fast acting.
They should be sized 1.25 to 1.5 times the input amperage of the drive. Refer to the installation
schematic for breaker sizing.
2. Each VFD should be fed by its own breaker. If multiple VFDs are to be combined on the same
breaker, each drive should have its own protection measure (fuses or miniature circuit breaker)
downstream from the breaker.
3. Input AC line wires should be run in conduit from the breaker panel to the drives. AC input power
to multiple VFDs can be run in a single conduit if needed.
4. The VFD should be grounded on the terminal marked PE.
STOP!
DO NOT connect incoming AC power to output terminals U, V, W. Severe damage to the drive
will result. Input power must always be wired to the L terminal connections (L1, L2, L3)
Output Power
1. Motor wires from each VFD to its respective motor MUST be run in a separate steel
conduit away from control wiring and incoming AC power wiring to avoid noise and
crosstalk between drives.
2. Load reactors: If the distance between the VFD and the motor is great, a load reactor should be
used between the VFD and the motor. The output reactor should be sized accordingly.
208/230V
– Load reactor should be used when distance exceeds 250 feet.
460/480V – Load reactor should be ordered when distance exceeds 50 feet.
575V – Load reactor should be ordered when distance exceeds 25 feet.
3. If the distance between the VFD and the motor is between 500 and 1000 FT, a dV/dT filter should
be used.
4. No contactor should be installed between the drive and the motor. Operating such a device while
the drive is running can potentially cause damage to the power components of the drive.
5. When a disconnect switch is installed between the drive and motor, it should only be operated
when the drive is in a STOP state.
Programming
Most VFD parameters are preprogrammed at the factory when proper information about the fan
motors is provided. However the 2 parameters below should be verified in the field during startup.
1. The Drive should be programmed for the proper motor voltage. Refer to parameter P107 in the
“Component Description - Variable Frequency Drive” chapter below.
P107 is set to 0 (Low) if motor voltage is 120 VAC, 208 VAC or 400 VAC. P107 is set to 1 (High)
if motor voltage is 230 VAC, 480 VAC or 575 VAC.
2. The Drive should be programmed for the proper motor overload value. Refer to parameter P108
in the “Component Description - Variable Frequency Drive” chapter below.
P108 is calculated as Motor FLA x 100 / Drive Output Rating (available in table below). P108 is
also indicated on the factory wiring schematic under the “Motor Power Circuit” column.
NOTE: Do NOT adjust minimum and maximum frequency on the VFD. Communication errors will
result between the control board and the VFD. These parameters should be adjusted through the
control panel only.