Fault definitions – Rockwell Automation MV SMC Flex Motor Controller (for Series K or later) User Manual
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Rockwell Automation Publication 1560E-UM051F-EN-P - June 2013
Chapter 7
Diagnostics
Fault Definitions
Table 8 - Fault Definitions for the SMC Flex
Fault
Description
Line Loss (F1, F2, F3)
The SMC Flex can determine if a line connection has been lost, and will indicate this
accordingly.
Shorted SCR
Shorted SCRs will be detected and starting will be prohibited by the SMC Flex.
Open Gate
Open gate indicates that an abnormal condition that causes faulty firing (e.g., open
SCR gate or faulty gate driver) has been sensed during the start sequence. The SMC
Flex controller will attempt to start the motor a total of three times before the
controller shuts down.
Power Pole PTC
Overtemperature
The power pole temperature in each phase is monitored. If the temperature rises
above the predetermined level, the unit will fault to protect the power pole. A reset
can be performed once the temperature falls below this level. This fault may also
represent loss of gate driver power during gating (MV applications only).
Motor PTC
A motor PTC can be connected to terminals 23 and 24. If the PTC parameter is
enabled and the PTC trips, the SMC Flex will trip and indicate a Motor PTC fault.
Open Bypass
Power Pole bypass contacts are monitored for proper operation. In the event of a
contact failure, the SMC Flex will indicate an Open Bypass fault.
No Load
The SMC Flex can determine if a load connection has been lost, and No Load fault
will be indicated.
Line Unbalance
(1)
(1) Phase loss, overvoltage and undervoltage protection are disabled during braking operation.
Voltage unbalance is detected by monitoring the three phase supply voltages. The
formula used to calculate the percentage voltage unbalance is as follows:
V
u
= 100 (V
d
/ V
a
)
V
u
: Percent voltage unbalance
V
d
: Maximum voltage deviation from the average voltage
V
a
: Average voltage
The controller will shut down when the calculated voltage unbalance reaches the
user-programmed trip percentages.
Overvoltage and
Undervoltage Protection
Overvoltage and undervoltage protection are user-defined as a percentage of the
programmed line voltage. The SMC Flex controller continuously monitors the three
supply phases. The calculated average is then compared to the programmed trip
level.
Underload
(2)
(2) Jam detection and underload protection are disabled during slow speed and braking operation.
Additional details regarding fault definitions can be found in
Underload protection is available for undercurrent monitoring. The controller will
shut down when the motor current drops below the trip level. This trip level, a
percentage of the motor’s full load current rating, can be programmed.
Overload Protection
Overload protection is enabled in the Motor Protection group by programming the:
• Overload class
• Overload reset
• Motor FLC
• Service factor
Refer to
for more information on Motor Protection.
Phase Reversal
Phase reversal is indicated when the incoming power to the SMC Flex controller is in
any sequence other than ABC. This pre-start protective feature can be disabled.
Coms Loss
The SMC Flex controller disables control through the serial communication port as
the factory default. To enable control, the Logic Mask found in the Communication
programming group must be set to “4.” With Series B human interface modules, this
can also be accomplished by enabling control logic through the Control Status
programming group.
If a Bulletin 20-HIM Human interface module or Bulletin 1203 communication
module is disconnected from the SMC Flex controller when control is enabled, a
Comm Fault will occur.
Network
Network faults are faults generated on the network external to the SMC Flex, and
are annunciated on the LCD display.