beautypg.com

Variable frequency drive (vfd) – Carrier 48/50PD05 User Manual

Page 53

background image

53

Variable Frequency Drive (VFD)

The VFD varies the frequency of the AC voltage supplied to the
indoor fan. (See Fig. 20 and Table 23.) This causes the variance in

the speed of the fan. The commanded fan speed is received by the

VFD from the AUX1 board as a 2--10vdc signal.
The AI1 DIP switch must be in the off (or towards “U”) position to

properly read the analog signal. There are three jumper wires that
must remain installed for proper operation. The VFD is mounted

behind the fan housing on the fan sled and the remote keypad is
mounted on the front of the fan housing for easy access. The VFD

is factory set to the auto mode for unit operation.

C09146

Fig. 20 -- Variable Frequency Drive (VFD)

Table 23 — VFD Connections

DISPLAY NAME

POINT DESCRIPTION

TYPE OF I/O

TERMINAL

NUMBER

TERMINAL

NAME

LOW VOLTAGE INPUTS

Shielded Cable Ground

Shield

1

SCR

F.SPD

Commanded Fan Speed

2---10vdc

2

AI1*

Analog Input 1 Common

Ground

3

AGND

Low Voltage Power (jumped to DI1 & DI4)

24v

10

24v

Low Voltage Common (jumped to DCOM)

Ground

11

GND

Discrete Inputs Common (jumped from GND)

Ground

12

DCOM

Discrete Input 1 (jumped from 24v)

Switch Input

13

DI1

Discrete Input 4 (jumped from 24v)

Switch Input

16

DI4

HIGH VOLTAGE

Voltage Leg from IFC---21

Voltage Input

U1

MAINS

Voltage Leg from IFC---22

Voltage Input

V1

MAINS

Voltage Leg from IFC---23

Voltage Input

W1

MAINS

Voltage Leg to IFM---3

Voltage Output

U2

MOTOR

Voltage Leg to IFM---2

Voltage Output

V2

MOTOR

Voltage Leg to IFM---1

Voltage Output

W2

MOTOR

* Requires the Al1 dip switch to be in in the Off (or towards “U”) position.

48/

50P

D