Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) - Manual (Page 134)

124 Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013
Chapter 9 Troubleshooting
SCR Replacement Procedure
A. Remove SCR Stack from Unit
For all types of SMCs, the stack requiring new SCRs must first be removed from
the unit as follows:
1. Remove all power from the equipment.
2. Service to phase a module may require removing the medium voltage door
and swinging out the low voltage panel (for 36-inch wide, two-high
cabinet only); see
Figure 50 .
3. Remove current loop cable (see Figure 49 ).
4. Unplug all fiber-optic cables from the gate-driver board. Unplug gate lead
connectors.
5. Disconnect the power cables from the terminals on the left side of the
heatsink assembly. Use care not to damage components. The sharing
resistors are fragile.
6. Remove two (2) nuts at bottom front of heatsink assembly so the module
can be removed using the pull handle. (Phase C requires angling the
module to clear the front cabinet flange.) Position fiber-optic cables and
wiring so they will not be damaged as the module is removed from the
cabinet.
7. Pull module out slowly, and slide onto a platform lift, or lift the module
out of the cabinet.
8. Place the module on a flat surface (see Figure 53 , Figure 56 and Figure 62 ).
When tilting the module, ensure that wires are not damaged.
TIP This procedure applies to 180A and 360A units < 5000V only.
IMPORTANT Refer to OEM documentation for SCR stack location in 1503E.
SHOCK HAZARD: To avoid shock hazard, ensure 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.
ATTENTION: The gray fiber-optic cables can be damaged if struck or
bent sharply. They have a locking feature which requires pinching the
tab on the connector and gently pulling straight out. The component on
the printed circuit board should be held to prevent damage.
ATTENTION: The heatsink assembly is heavy (approx. 25 kg [55 lb] or
greater). To avoid injury, always use two people to remove and handle
the assembly. Place the heatsink on a cart to aid in its transport.