Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control - Manual (Page 75)

Rockwell Automation Publication 7000A-UM200C-EN-P - June 2014 75
Component Definition and Maintenance Chapter 3
Replacing the SGCT
The Symmetrical Gate Commutated Thyristor (SGCT or device) with attached
circuit board is located within the PowerCage assembly.
SGCTs must be replaced in matched sets:
• 3300V and 4160V systems use sets of two
• 6600V systems use sets of three
The SGCT and associated control board are a single component. There will
never be a time when the device or the circuit board will be changed individually.
There are four LEDs on the SGCT; the following table describes their functions:
1. Ensure there is no power to the equipment.
Note the position of the fiber optic cables for assembly.
2. To remove the SGCT, it is necessary to remove the gate driver power cable and
fiber optic cables. Exceeding the minimum bend radius (50 mm [2 in.]) of
the fiber optic cables may result in damage.
If installed, remove the SPS snubber connector ( J1 on the SPS board) and
remove the SPS mounting bracket with the SPS board.
3. Remove the load on the clamp head assembly as described on page 83 .
4. Two brackets secure the board to the heatsink. Loosen the captive screws until
the circuit board is free. It may be necessary to adjust the position of the
heatsinks to allow free movement of the SGCT.
LED 4 Green Solid Green indicates that the Power Supply to the Card is OK
LED 3 Green Solid Green indicates that the Gate-Cathode resistance is OK
LED 2 Yellow LED ON indicates the gate is ON, and Flashes alternately with LED 1 while
gating
LED 1 Red LED ON indicates the gate is OFF, and Flashes alternately with LED 2 while
gating
ATTENTION: To prevent electrical shock, ensure the main power has been
disconnected before working on the drive. Verify that all circuits are voltage
free using a hot stick or appropriate voltage-measuring device. Failure to do so
may result in injury or death.
ATTENTION: The fiber optic cables can be damaged if struck or bent sharply.
The minimum bend radius is 50 mm (2 in.). The connector has a locking feature
that requires pinching the tab and gently pulling straight out. The component
on the printed circuit board should be held to prevent damage