Rockwell Automation SA3000 High Power Modules - Manual (Page 34)

4-2 High Power SA3000 AC Power Modules
4.2 Power Module Tests with Input Power Off
Use the following procedure to perform the SA3000 Power Module tests:
Step 1. Turn off and lock out DC input power.
Step 2. Wait ten minutes to allow the DC bus voltage to dissipate.
Step 3. Open the Power Module’s cabinet doors and measure the voltage across
each pair of DC bus bars, 347 A,B,C (+ bus) and 345 A,B,C (- bus), with an
external voltmeter to ensure the DC bus capacitors are discharged before
touching any internal components. See figure 4.1.
Step 4. Disconnect the motor from the Power Module.
Step 5. Check the DC bus fuses.
Be sure to check the DC bus fuses for continuity if an IGBT phase module or
fuse fails in a 972A or 1457A Power Module. Excessive current may have
damaged the DC bus fuses. It is recommended that the DC bus fuses be
replaced whenever an IGBT phase module or fuse fails due to a fault current.
If the DC bus fuses have opened in Power Module A, a bus fault will be
generated. If the DC bus fuses have opened in Power Modules B or C, a bus
fault will not be generated, but an Instantaneous Overcurrent (IOC) fault will
be indicated. This may be the only indication of a blown fuse in Power
Modules B and C.
Step 6. If a fuse is blown, use a multimeter to check the DC bus, bus capacitors,
output terminals, and the output IGBTs. See tables 4.1 and 4.2.
Step 7. If a capacitor is defective, replace the capacitor bank assembly as described
in section 4.4.5. If an IGBT is defective, refer to section 4.4.2.
!
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. Open the cabinet
doors and check the voltage across the DC bus bars, 347 A,B,C (+ bus)
and 345 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.