Rockwell Automation SA500 DC Bus Supply - Manual (Page 24)

3-10 SA500 DC Bus Supply
If external resistors are to be used, connect the wires from the resistors to the
terminal block at the top of the bus supply. A notch in the front cover allows
the wires to be routed from the terminal block even when the front cover is
installed.
Step 5. Apply power to the input wiring and check that the voltages are within
operating parameters. Voltage specifications are given in Appendix A.
Step 6. Re-attach the bus supply’s front cover.
3.6 Replacing the DC Bus Supply
Use the following procedure to replace a DC bus supply:
Step 1. Turn off and lock out AC input power to the bus supply.
Step 2. Wait five minutes to allow the DC bus voltage to dissipate.
Step 3. Measure the DC bus potential across the POS and NEG terminals of the DC
bus supply and at each Power Module before working on the unit.
When the DC bus potential is down to less than 5V, touch a 50
Ω,
50 W or
larger resistor across the POS and NEG terminals for 20 seconds to allow
any remaining DC bus voltage to dissipate.
Remove the resistor and re-measure the DC bus potential to ensure the DC
bus capacitors are completely discharged before touching any internal
components.
Step 4. Disconnect the input power wires from the L1, L2, and L3 terminals.
Step 5. Disconnect the DC bus wires from the POS, NEG, and GND terminals.
Step 6. Disconnect the external braking resistor (if used) from the terminal block at
the top of the DC bus supply.
Step 7. Remove the screws that attach the bus supply to its mounting surface.
Step 8. Install the replacement bus supply by following steps 3 through 7 in reverse
order.
!
ATTENTION: DC bus capacitors retain hazardous voltages after input
power has been disconnected. After disconnecting input power from the
DC bus supply, wait five (5) minutes and then measure the voltage at the
POS and NEG terminals of the DC bus supply and each Power Module
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.