Rockwell Automation SB3000 AC Power Modules - Manual (Page 56)

4-18 SB3000 Power Modules (Rittal)
4.5.4 Replacing a Bus Capacitor Assembly
Use the following procedure to replace a DC bus capacitor assembly:
Step 1. Turn off and lock out the AC input power.
Step 2. Wait ten minutes to allow the DC bus voltage to dissipate.
Step 3. Look at the built-in DC Bus Voltage meter. When the DC bus potential is
down to zero volts, open the SB3000 Power Module cabinet's doors and
measure the DC bus potential across the DC bus bars, 1247 A,B,C (+ bus)
and 1145 A,B,C (- bus), with an external voltmeter before working on the unit.
See figure 4.1.
Step 4. Remove all three IGBT assemblies (U, V, and W). Refer to section 4.5.2 for
information on IGBT assembly removal.
Step 5. Remove the AC input power wiring by removing the bolt from the LEM stud
spacer. This wiring consists of three insulated, tinned-copper straps which
have color-coded bands (orange, yellow, and purple).
Step 6. Remove the LEM device control wiring. Needle-nose pliers may be useful in
removing the three wire connectors.
Step 7. Remove the three LEM devices. Four screws attach each LEM device to the
capacitor bank.
Step 8. Remove the three insulator blocks. Each insulator block is secured by two
hex nuts.
Step 9. Remove the power cable wiring harnesses from the top of the capacitor
bank. The two wiring harnesses have color-coded bands. The positive bus
bar cable has a red band while the negative bus bar cable has a gray band.
Step 10. Remove the control wiring from the top of the capacitor bank.
Step 11. Remove the capacitor bank's four mounting screws. Two are located at the
top of the capacitor bank and two at the bottom.
Step 12. Slide the capacitor bank out of the cabinet.
Step 13. Install the new capacitor bank assembly by following steps 1 through 12 in
reverse order.
Step 14. Close the cabinet doors and reapply power to the SB3000 Power Module.
!
ATTENTION: DC bus capacitors retain hazardous voltages after input
power has been disconnected. After disconnecting input power, wait ten
(10) minutes for the DC bus capacitors to discharge, then look at the
built-in DC bus voltage meter. When the voltage is down to zero (0) volts,
open the cabinet doors and check the voltage across the DC bus bars,
1247 A,B,C (+ bus) and 1145 A,B,C (- bus), with an external voltmeter
to ensure the DC bus capacitors are discharged before touching any
internal components. Failure to observe this precaution could result in
severe bodily injury or loss of life.