Rockwell Automation FlexPak 3000 Digital DC Drive Version 4.3 - Manual (Page 149)

Troubleshooting the FlexPak 3000 Drive 13-17
Step 10. Set PHASE FIRE TEST DELTA (P.309) to 55 degrees. Slowly increase PHASE
FIRE TEST DELTA until a steady pattern of “bumps” appears on the
oscilloscope. If all thyristors in the selected bridge are operating, there will
be six bumps per AC line cycle, similar to the example in figure 13.1. If any
bumps are missing, one or more thyristors are not conducting, similar to the
example in figure 13.3.
Note that conduction will not begin until the firing angle is sufficiently
advanced (
PHASE FIRE TEST DELTA (P.309) more than 60 degrees). A rate
limit block limits the rate of change of firing angle advances to prevent
sudden increases in current. To prevent the drive from entering continuous
conduction during this test,
PHASE FIRE TEST DELTA (P.309) should not
exceed 89 degrees.
Step 11. Press to stop the armature phase fire test.
Step 12. Turn off power to the drive (lockout and tag as necessary).
Step 13. Either unlock the motor armature or remove the dummy load and reconnect
the motor armature leads.
If the motor field winding was disconnected, reconnect it and return jumper
J20 to its original position (typically
ENABLE ).
Figure 13.3 – Thyristors Fail to Conduct