Functional Description 1-19
7000-TD002A-EN-P – September 2007
The PowerFlex 7000 drive tests for the failure of the power
semiconductors (SCRs or SGCTs) before running and while running.
The method used to detect failed devices is different for starting
(offline diagnostics) and for running (on-line diagnostics), but the
same hardware is used in both situations. The drive control receives
a feedback signal via a fiber-optic cable from each device gate
driver, which can indicate whether or not it is healthy. SCR
diagnostics are based on sensing the voltage across the device while
SGCT has smart diagnostics built in the gate driver board. The
feedback and the gating have a certain relationship when the device
is healthy or failed. This is shown in Figure 1.10 and will be
described in detail in following sections. The description applies to
all 6P, 18P and PWM PowerFlex 7000 drives. In the drive, the test
points are available on the OIBB for monitoring the gating and
diagnostic signals. In order to understand how the diagnostics work,
it is important to understand the relationship between fiber optic
signals and the logic levels on the test points. This is summarized in
Table 1.B and Table 1.C.
Table 1.B
OIBB Transmitter(TX) TP_CMD on OIBB Device Status
LIGHT 0V ON
NO LIGHT 5V OFF
Table 1.C
OIBB Receiver(RX) TP_DIAG on OIBB
LIGHT 0V
NO LIGHT 5V
Power Semiconductor
Diagnostics
To Next Page
Loading...
Need help?
General
