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REMOTE KEYPAD REFERENCE
This section only applies when a unit with the factory-installed
Variable Frequency Drive (VFD) option is equipped with the
field-installed Remote VFD Keypad (P/N CRDISKIT001A00).
On single package rooftop units and fan coils equipped with the
factory-installed VFD option, the supply fan speed is controlled
by a 3-phase VFD. See Fig. 10-27 for the location of the VFD in
the various units covered in this manual.
The VFD is powered during normal operation to prevent conden-
sation from forming on the boards during the off mode and is
stopped by driving the speed to 0. The units use ABB VFDs. The
interface wiring for the VFDs is shown in Fig. 29 and 30. Termi-
nal designations are shown in the Terminal Designation tables (see
Tables 32 and 33). Configurations are shown in the VFD Parame-
ters tables (see Appendix Tables A-G on pages 41-48).
Variable Frequency Drive
The VFD switches the indoor fan motor speed between full/high
speed (60 Hz motor operation) and reduced/low speed (40 Hz
motor operation) as required by ASHRAE 90.1-2016 and
IECC-2015 requirements for two-stage HVAC units. The VFD
is factory-configured to match the current and power require-
ments for each motor selection and all wiring connections are
completed by the factory; no field adjustments or connections
are necessary.
While the basic VFD retains all of its standard capabilities, the
2-speed indoor fan system application uses only a limited portion
of these features to provide two discrete output speeds to the mo-
tor. Consequently the VFD is not equipped with a keypad. A key-
pad is available as an accessory (P/N CRDISKIT001A00)
ACH550/ACS320 or (P/N CRDISKIT003A00) ACH580 for
field-installation or expanded service access to VFD parameter
and troubleshooting tables.
CAUTION
CONFIGURATION OVERRIDE HAZARD
Do not use start-up assistant on this VFD application! Use of
start-up assistant will override the factory VFD configurations!
The 2-Speed Indoor Fan system control circuit inputs to the VFD
are 24-VDC signals.
•
For ACS320 VFDs the voltage is sourced from the VFD at its
terminal 9 (+24 V). 2-Speed Indoor Fan system speed inputs
are received at terminals 13 (DI-2) for low speed (40 Hz) mo-
tor operation and 14 (DI-3) for high speed (60 Hz) motor op-
eration. See Table 32 and Fig. 29.
•
For ACH550/580 VFDs the voltage is sourced from the VFD
at its terminal 10 (+24 V). 2-Speed Indoor Fan system speed
inputs are received at terminals 14 (DI-2) for low speed
(40 Hz) motor operation and 13 (DI-3) for high speed (60 Hz)
motor operation. See Table 33 and Fig. 30.
When neither input is present, the VFD will shut the fan motor
off. There is no separate indoor fan contactor required in this
application.
The VFD used in the 2-Speed Indoor Fan system has soft start
capabilities to slowly ramp up the speeds, eliminating any high
inrush of air volume during speed changes. It also has internal
over current protection for the fan motor.
INDOOR FAN MOTOR
The indoor fan motors used with the VFD are specially manufac-
tured for use with VFD power circuits. The motor winding insula-
tion is specially formulated to resist breakdown due to voltage
stress issues. The motor shaft includes grounding rings to prevent
damage to bearings caused by grounding currents. Replace these
motors with Factory Authorized Parts available from Replace-
ment Components Division (RCD).
Table 32 — ACS320 VFD Terminal Designations
TERMINAL
U1
V1
Three-Phase main circuit input power supply
W1
U2
Three-Phase AC output to motor, 0V to maximum
V2
input voltage level
W2
10 (GND)
Factory-supplied jumper
11 (COMMON)
9 (24 VDC)
Run (factory-supplied jumper)
12 (DI-1)
9 (24 VDC)
Start Enable 1 (factory-supplied jumper). When
15 (DI-4)
opened, the drive goes to emergency stop
13 (DI-2)
Factory wired for 24 Vdc input from Fan Speed
14 (DI-3)
Board
ACS320 VFD TERMINAL STRIP
9
10
PNK
Fig. 29 — ACS320 VFD Wiring
Table 33 — ACH550/580 VFD Terminal Designations
TERMINAL
U1/L1
V1/L2
Three-Phase main circuit input power supply
W1/L3
U2 / T1/U
Three-Phase AC output to motor, 0-v to maximum
V2 / T2/V
input voltage level
W2 / T3/W
11 (GND)
Factory-supplied jumper
12 (COMMON)
10 (24 VDC)
Run (factory-supplied jumper)
13 (DI-1)
10 (24 VDC)
Start Enable 1 (factory-supplied jumper). When
16 (DI-4)
opened, the drive goes to emergency stop
14 (DI-2)
Factory wired for 24 vdc input from Fan Speed
15 (DI-3)
Board
ACH550/580 VFD TERMINAL STRIP
10
11
PNK
Fig. 30 — ACH550/580 VFD Wiring
25
FUNCTION
11
12
13
14
15
YEL
WHT
FUNCTION
12
13
14
15
16
YEL
WHT
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