26 Rockwell Automation Publication 20P-TG002B-EN-P - February 2018
Chapter 2 Component Test Procedures
Power Component Test
Procedures
Check the Armature SCR Modules
The frame B PowerFlex DC drive armature supply consists of three (non-
regenerative drives) or six (regenerative drives) SCR modules mounted on heat
sinks within the legs assemblies. A malfunction of any of these devices will be
indicated by either an Overcurrent fault (F13), blown or tripped incoming
protection devices, or erratic motor operation. The following procedure can be
used if an armature bridge component malfunction is suspected.
1. Read the General Safety Precautions on page 10
.
2. Verify that contactor power (if used) is removed.
3. Verify that power to an external field supply (if used) is removed.
4. Check the anode to cathode junction of each SCR. With a digital
multimeter set to Ohms, measure the resistance across the SCRs (lead
orientation is not critical).
• For regenerative drives, see Tabl e 2
on page 26 and Figure 6 on
page 27
.
• For non-regenerative drives, see Tabl e 3
on page 28 and Figure 7 on
page 28
.
If a low resistance is detected, determine which SCR module(s) is/are
damaged based on the tables below and replace that module (see
page 80
).
Table 2 - SCR Anode to Cathode Junction Measurements for Regenerative Drives
On SCR Module SCR Measure from
Terminal
To Terminal Nominal Meter Reading
1 1 U C “open circuit” or “MΩ” range
4U D
22V C
5V D
33W C
6W D
01 01 U C
04 U D
02 02 V C
05 V D
03 03 W C
06 W D
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