Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 273)

Functional Description 5-19
7000 “B” Frame 7000-UM150I-EN-P – June 2013
For most Warnings no action is taken and drive maintains its normal
operation. A warning could be an indication of a problem in drive
e.g. an Air Filter warning is an indication of a blocked air filter. In
addition there are a few warnings in the drive that may cause
momentary interruption in the operation of the drive e.g. Master UV,
Line Loss or Bus Transient. The action taken is similar to a Class1
fault and the normal operation is resumed once the transient
condition has disappeared. If a drive experiences Master UV or Line
Loss, then Auto Restart Dly (3) should be set to a non-zero value in
order to resume normal operation.
It is important to understand how contactors (input and output)
behave in an event of fault. If the input contactor is set for Not
Running or All Faults via parameter Input ContCfg (1), then the
contactor opens on any fault (Class1, Critical or Class2) in the drive.
This happens after the dc link current has been brought to zero and
the gating for all converters disabled. If the contactor is set for
Critical Flt, then the contactor will open only when a critical fault
(explained above) happens in the drive. For all other faults (Class1 or
Class2) the input contactor will remain closed after the drive has
been shut off.
An output contactor, whose configuration is specified by Output
ContCfg (5), opens for any fault in the drive. This happens after the
dc link current has been brought to zero and the gating for all
converters disabled.
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 5.10. The following
section describes the diagnostics in detail. The description applies to
all 6P, 18P and PWM PowerFlex 7000 drives.
Power Semiconductor
Diagnostics