Rockwell Automation FlexPak Plus NRG DC Drive - Manual (Page 20)

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5.3 Motor Problems - Do not overlook the possiĆ
bility that the malfunction may be located in the drive
motor. The following steps should become part of a
troubleshooting routine:
D Recheck all motor connections for firmness and
correct identification.
D Check that no obvious grounds have occurred on
any of the wires. However, do not use a megger
when checking for grounds unless the motor wiring
to the FlexPak Plus controller is completely disconĆ
nected.
D A voltĆohmmeter (VOM) may be used for ground
checking without disconnecting conductors to the
FlexPak Plus controller.
D Check the field windings for open or short conditions.
D Check continuity through the armature and brushes.
Use terminals A1 and A2 at the Controller as test
points.
Figure 5.1 - Unidirectional Control Circuit
(simplified)
5.4 Mechanical - It may be that the malfunction is
a simple mechanical problem. The load on the drive
motor may be too large, or it may have too high an inerĆ
tia. The results are long stopping times and currentĆlimit
starting demands. Thus, the freedom of motion of the
load device should be considered.
5.5 Controller Malfunctions - Table 5.A presĆ
ents an organized troubleshooting sequence based on
a symptom/probable cause/suggested procedure apĆ
proach. They develop from the most simple, obvious
malfunction to more complex ones.
5.6 Schematics, Diagrams - In order to aid with
the troubleshooting process, various schematics and
diagrams are included. Note that these drawings are the
latest revisions as of the date of publication of this
manual. The manufacturer cannot guarantee that subĆ
sequent changes will not occur; although, if any do,
they should be minor. In cases of doubt, contact your loĆ
cal Reliance Electric Sales Office.
Figure 5.2 - Bidirectional Control Circuit
(simplified)
Symptom Probable Cause Recommended Procedures