168
APPENDIX C — VFD INFORMATION
On variable air volume units with optional VFD, the supply
fan speed is controlled by a 3-phase VFD. The VFD is located
in the supply fan section behind a removable panel. The VFD
speed is controlled directly by the
Comfort
Link controls
through a 4 to 20 mA signal based on a supply duct pressure
sensor. The VFD has a display, which can be used for service
diagnostics, but setup of the building pressure and control loop
factors should be done through the scrolling marquee display.
The VFD is powered during normal operation to prevent
condensation from forming on the boards during the off mode
and is stopped by driving the speed to 0 (by sending a 4 mA
signal to the VFD).
The A Series units use ABB VFDs. The interface wiring for
the VFDs is shown in Fig. A. The VFD connects through
an isolation board to the 4 to 20 mA RCB board. Terminal
designations are shown in Table A. Configurations are shown
in Table B.
Table A — VFD Terminal Designations
TERMINAL
FUNCTION
U1
V1
W1
Three-Phase Main Circuit Input Power Supply
U2
V2
Three-Phase AC Output to Motor, 0 V to
W2
Maximum Input Voltage Level
X1-11 (GND)
X1-12 (COMMON)
Factory-supplied jumper
X1-10 (24 VDC)
X1-13 (DI-1)
Run (factory-supplied jumper)
X1-10 (24 VDC)
Start Enable 1 (Factory-supplied jumper). When
X1-16 (DI-4)
opened the drive goes to emergency stop.
X1-2 (AI-1)
X1-3 (AGND)
Factory wired for 4 to 20 mA remote input
Fig. A — VFD Wiring
A48-7712
Summary of Contents for Carrier Weathermaker 48A2
Page 105: ...105 Fig 20 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units...
Page 106: ...106 Fig 21 Typical Auxiliary Control Box Wiring Schematic...
Page 107: ...107 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown a48 8357...
Page 108: ...108 TO NEXT PAGE Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown A48 7296...
Page 109: ...109 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont A48 8358...
Page 110: ...110 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown a50 8228...
Page 111: ...111 Fig 25 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown...
Page 112: ...112 Fig 26 Typical Low Ambient Controls Option Wiring...
Page 113: ...113 Fig 27 Typical Small Chassis Component Location Size 020 035 Units...
Page 114: ...114 Fig 28 Typical Large Chassis Component Locations Size 040 060 Units...
Page 118: ...118 Fig 30 Economizer Control Board ECB1 and VAV Control Board ECB2 A48 7706...
Page 142: ...142 A48 3733 Fig 56 Main Burner Removal...
Page 176: ...176 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716...
