Figure 2.15 Troubleshooting Motor Power Supply - Bard D25A2PA Installation And Service Instructions Manual

SPECIFIC TROUBLESHOOTING –
48VDC Blower Motor
To troubleshoot the 48VDC blower motor, check for
proper voltage and commands to the motor controller
from the wall-mount unit. Under a command for blower,
Motor Controller
Color
Molex Plug
1 Red
2
3
4 Orange
5 Black
6
7 Red
8
9 Black
48VDC
TABLE 2.5
Troubleshooting the 48VDC Indoor Blower Motor
Function
0-10 VDC input, varying voltage input between 0-10 VDC dictates the motor speed/
SPEED INPUT
CFM delivery
Start Command – a contact closure between this wire and the control ground (Pin 5)
RUN
will issue and order for the motor to start.
CONTROL GROUND Control Ground for both start-stop function and speed control voltage
52 VDC (+) "+" VDC power supplied to motor
52 VDC (-) "-" VDC power supplied to motor
FIGURE 2.15
Troubleshooting Motor Power Supply
Female Plug
disconnect the 9-pin Molex plug connecting the motor
control to the wall-mount unit control wiring harness
(this Molex is located in the chassis wall of the control
panel) and test for the items in Table 2.5 (see Figure
2.15 below and Figures 2.16 and 2.17 on page 40).
Description of Application
Motor Power Supply: With the meter set to VDC, place
the black (–) lead on Pin 9 and the red (+) lead on Pin 7
of the female portion of the Molex-style plug connecting
the motor controller to the back of the wall-mount control
cabinet. Nominal voltage should be 48VDC to 54VDC.
Note the plug-pin "flats" for proper orientation of the plug.
Manual 2100-643C
Page 39 of 59