Rockwell Automation 20D DC SCR Precharge Module - Manual (Page 26)

2-4 Start-Up / Troubleshooting
Troubleshooting Table 2.B provides information for troubleshooting the DC SCR Precharge
Module.
Table 2.B Possible Symptoms and Corrective Actions
Symptom Cause/Indication Corrective Action
DC output voltage loss DC bus:
• Short circuit or
• Low line
1. Check 3-phase AC incoming power for
undervoltage or phase loss.
2. Check the protection Precharge fuse F1.
3. After precharge is completed, verify that
the values of the “+DCin” and “+DCout”
voltages are within 1 volt.
4. Contact your local RA Sales Office.
Loss of 120 VAC or 24
VDC supply voltage 1. Verify 120 VAC or 24 VDC supply input
voltage is present at control terminals
TB2A-1 and TB2A-2.
2. Enable the contactor function.
3. Contact your local RA Sales Office.
Heat sink overtemperature
(contacts TB2A-9 and
TB2A-10 have opened) Heat sink temperature
exceeds maximum rating 1. Verify that the maximum ambient
temperature has not been exceeded.
2. Check Overtemperature Switch “T” at
control terminals TB2A-9 and TB2A-10
that has normally closed contacts.
3. Verify 120 VAC supply input voltage at
control terminals TB2A-3 and TB2A-4.
4. Verify fan for correct operation. Airflow
should be outward from the unit.
5. Check for excess load on the DC SCR
Precharge Module.
6. Check for proper spacing around the DC
SCR Precharge Module.
7. Contact your local RA Sales Office.