Rapid-Air PALLET MASTER (PMD) HIGH SPEED: 35, 50 & 100 SERIES - Manual (Page 16)

Troubleshooting
The printed circuit boards in these controls are built utilizing the surface mount technology and
are not considered to be field repairable. However, few problems originate from the printed cir-
cuit board. By following the procedures listed below, a trained service technician can trouble-
shoot and solve most problems.
Basic Considerations
Before proceeding check the following:
1) AC input power must be the same voltage as shown on the control nameplate.
2) Check the motor nameplate for armature and field. With 115 VAC input the motor should
have a 90 VDC armature and a 100 VDC field. PM motors do not have a field winding, and
no connections to F1 and F2 should be made.
3) Check that the terminal block connections are consistent with that shown on the connection
diagrams.
4) Check to see that the line fuse(s), F1 and F2, are the correct value (20 amperes normal
blow) and are not blown. Also check the field fuse, F3, (1.5 amperes normal blow).
SAFETY WARNING: When changing these fuses the power line MUST be discon-
nected from the control to prevent contact with dangerous voltages which could cause
serious injury or fatality.
I. Heed and follow the safety warning at the beginning of the calibration information.
II. Set direction select speed adjust pot to its center position. If speed adjust pot is wired for
unidirectional operation, set it at full CCW. Apply AC power. If field fuse blows, discon-
nect AC power from control and check:
a) Motor cable or motor field may be shorted or grounded. Disconnect F1 AND F2. A
resistance reading across the motor field should read approximately 100 to 1000
ohms, depending on the horsepower rating of the motor. A reading from either side
of the field to the motor frame should show open. (use high ohm scale)
III. Reconnect motor to control, reconnect power line to control and advance the direction select
speed adjust pot to maximum FORWARD speed (full CW). If speed adjust pot is wired for
unidirectional operation advance it to maximum speed (full CW).
a) If line fuse(s) blow:
1) Motor armature or motor cable may be shorted or grounded. Disconnect AC power
from control and disconnect A1 and A2. An ohmmeter reading across the motor ar-
mature should read approximately 1 to 100 ohms, depending on the horsepower of
the motor. A reading from either side of the armature to the motor frame should
show open (use high ohm scale).
2) Motor field circuit may be open. Check for correct motor field resistance as de-
scribed in II.a.
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