90 Rockwell Automation Publication 7000-UM202D-EN-P - May 2018
Chapter 2 Power Component Definition and Maintenance
Replacing SCR and SCR Self-Powered Gate Driver Boards (SPGDB)
Replacing the SCR is similar to replacing the SGCT, except that you can
replace the SCR and circuit board independently of one another.
1. Isolate and lock out all power to the drive.
2. Note the position of the fiber optic cables for reassembly.
3. To remove the SCR and SCR SPGDB, first remove the gate driver
power supply connector (from snubber circuit), the fiber optic cable,
and the SCR gate-cathode connection. Exceeding the minimum bend
radius
(50 mm / 2 in.) of the fiber optic cables may result in damage.
4. Remove the load on the clamp head assembly as described under
Checking Clamping Pressure
on page 93.
5. Loosen the 2 captive screws with a long Phillips screwdriver until the
circuit board is free. If necessary, adjust the position of the heatsinks to
allow free movement of the SCR.
6. Slide the SCR and SCR SPGDB straight out.
7. While grounded, unplug the gate-cathode connector from the SCR
SPGD board.
To replace the SCR, follow steps 8…11 and 15…18.
To replace the SCR SPGDB, follow steps 12…18.
ATTENTION: To prevent electrical shock, disconnect the main power 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: You may damage the fiber optic cables if you strike or bend
them 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. Hold the component on the printed circuit board to prevent damage.
ATTENTION: Static charges can destroy or damage the SCR and SCR SPGD
board. Properly ground yourself before removing the replacement SCR and
SCR SPGD board from the protective anti-static bag. Using damaged circuit
boards may also damage related components. Use a grounding wrist strap
for handling sensitive circuit boards.
IMPORTANT Never adjust the orientation of the SCR using the gate and cathode leads.
These connections are sensitive; adjust the device orientation by turning the
device itself.
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