Rockwell Automation SB3000 AC Power Modules - Manual (Page 57)

Diagnostics and Troubleshooting 4-19
4.6 Performing the Bridge Test
Important: This test is normally performed at the factory. It should not be necessary
to perform it again unless the power devices or fiber-optic cables have
been replaced.
The bridge test is used to verify fiber-optic gate cabling connections by test firing the
IGBTs one at a time. As the IGBTs fire, the LEDs on the corresponding GDI module in
the PMI rack will turn on and off in the following sequence:
1. U- (Lower Power Device)
2. U+ (Upper Power Device)
3. V- (Lower Power Device)
4. V+ (Upper Power Device)
5. W- (Lower Power Device)
6. W+ (Upper Power Device)
If the LEDs do not turn on and off in this order, the fiber-optic gate cables have been
connected incorrectly and must be reconnected as shown on the wiring diagrams.
Note that three-phase AC input power must be off and the DC bus capacitors must be
discharged before the cables can be reconnected.
Three-phase AC input power to the SB3000 Power Module must be turned off and the
inverter must be disconnected before the bridge test can be enabled. When the bridge
test is running, the pre-charge contactor will be closed. 115 VAC control power must
be applied for the pre-charge contactor. When the bridge test is turned off, the
pre-charge contactor will open.
The PMI Processor will prevent the bridge test from executing if the DC bus voltage is
greater than 10 VDC. However, the PMI Processor cannot prevent three-phase AC
input power from being applied once the bridge test has been started. If three-phase
AC input power is turned on while the bridge test is in progress, a line-to-line short
circuit will result which may result in bodily injury and damage to the SB3000 Power
Module.
Use the following procedure to perform the bridge test:
Step 1. Disconnect, lockout, and tag the three-phase AC input power to the SB3000
Power Module.
Step 2. Ensure that the DC bus is fully discharged. Refer to section 4.2.
Step 3. Enable the bridge test through register 100/1100, bit 2, and bits 10, 11, or 12,
as applicable.
Step 4. Verify that the LEDs turn on and off in the order described. If the LEDs do not
turn on and off in the proper order, reconnect the fiber-optic gate cables as
shown on the wiring diagrams.
!
ATTENTION: Disconnect and lock out three-phase AC input power to
the SB3000 Power Module before enabling the bridge test. Ensure that
three-phase AC input power cannot be turned on while the bridge test is
running. If three-phase AC input power is turned on while the test is
running, a line-to-line short circuit will occur. Failure to observe this
precaution could result in bodily injury.