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Rockwell Automation Publication 1560F-UM001A-EN-P - June 2019
Chapter 9
Troubleshooting
Power Circuit
Troubleshooting
Thyristor (SCR) Testing
If a power semiconductor is suspected of malfunctioning, it may be checked as
follows:
1. Remove all power from the equipment.
2. Measure DC resistance per the following chart:
Table 63 - SCR Resistance Measurements
3. If a short circuit is suspected, the SCR must be isolated from all
surrounding circuitry (i.e. unplug gate and cathode leads, and remove
snubber and resistor circuit leads from the driver boards). Measure
resistance to confirm state of the SCRs. If the SCRs are not shorted,
proceed to snubber and resistor circuit testing, following this procedure.
4. If a faulty device is found, the entire heatsink assembly must be removed.
5. Complete heatsink assemblies with matched SCRs are available as a
renewal part (see
). In most cases, the assembly can be
dismantled to replace the SCRs.
SHOCK HAZARD:
To avoid shock hazard, ensure the main power has
been disconnected before working on the controller, motor or control
devices. Verify that all circuits are voltage free using a hot stick or
appropriate voltage measuring device. Failure to do so may result in
burns, injury or death.
Location of
Probes
1000V
1300V
1500V
2300V
3300V
4160V
5500V
6900V
Cathode to Cathode
(KΩ)
(1)
(1) Measured between terminals “Cathode” on CLGO Boards, upper two or between two within a phase.
—
—
—
—
22…30 23…31
21…29
24…32
Cathode to Cathode
(KΩ)
(2)
(2) Measured between terminals “Cathode” on CLGO Boards, top to bottom within a phase.
17…23 19…25 20…27 21…29 40…53 43…57 60…90
(3)
(3) Measured between line and load terminals within a phase.
64…84
(3)
Cathode to Gate (Ω) 10…40 10…40 10…40 10…40 10…40 10…40
10…40
10…40
TIP
The actual resistance value depends on the ohmmeter used, the particular
brand/rating of SCR and external circuit influences. It is impossible to
accurately measure the condition of the SCR when it is unclamped!
ATTENTION:
For heatsink assemblies containing four or more SCRs, the
entire matched set shall be replaced. Devices connected in series must
have performance specifications matched for proper operation. Failure
to use matched sets may result in damage to the devices.
Summary of Contents for SMC-50
Page 10: ...10 Rockwell Automation Publication 1560F UM001A EN P June 2019 Table of Contents Notes ...
Page 12: ...12 Rockwell Automation Publication 1560F UM001A EN P June 2019 Preface Notes ...
Page 68: ...68 Rockwell Automation Publication 1560F UM001A EN P June 2019 Chapter 2 Installation Notes ...
Page 120: ...120 Rockwell Automation Publication 1560F UM001A EN P June 2019 Chapter 4 Programming Notes ...
Page 130: ...130 Rockwell Automation Publication 1560F UM001A EN P June 2019 Chapter 5 Metering Notes ...
Page 156: ...156 Rockwell Automation Publication 1560F UM001A EN P June 2019 Chapter 8 Diagnostics Notes ...
Page 198: ...198 Rockwell Automation Publication 1560F UM001A EN P June 2019 Chapter 10 Maintenance Notes ...
Page 284: ...284 Rockwell Automation Publication 1560F UM001A EN P June 2019 Appendix H Spare Parts Notes ...
Page 286: ...286 Rockwell Automation Publication 1560F UM001A EN P June 2019 Appendix I Accessories Notes ...
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