Rockwell Automation 7763 Medium Voltage OneGear SMC Flex Motor Controller (10-15 kV) - Manual (Page 84)

84 Rockwell Automation Publication 7760-UM001D-EN-P - October 2014
Chapter 6 Diagnostics
Line Unbalance
(1)
Voltage unbalance is detected by monitoring the three phase supply voltages. The formula used to calculate the percentage voltage
unbalance is as follows:
• Vu = 100 (Vd / Va)
• Vu: Percent voltage unbalance
• Vd: Maximum voltage deviation from the average voltage
• Va: Average voltage
The controller will shut down when the calculated voltage unbalance reaches the user-programmed trip percentages.
Overvoltage and Undervoltage Protection (1) 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) 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 Chapter 5 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. Other settings could cause this fault (see Table 8.D).
Network Network faults are faults generated on the network external to the SMC Flex, and are annunciated on the LCD display.
Ground Fault Ground faults are based on feedback from the user supplied 825 CT detecting ground fault currents. Ground fault parameters of level
and time delay must be programmed for proper operation.
Excess Starts/Hour Excess starts/hour is displayed when the number of starts in a one hour period exceeds the value programmed.
Power Loss Power loss indicates that an input power phase is not present. The controller’s LCD display will identify the missing phase. If all three
phases are absent when a start command is issued, the LCD will display “Starting” without motor rotation.
Line Loss (F41, F42, F43) During expected SCR gate periods, the power pole voltage and currents are monitored. If the SCR conduction is not continuous, a fault
is indicated.
(1) Phase loss, overvoltage and undervoltage protection are disabled during braking operation.
(2) Jam detection and underload protection are disabled during slow speed and braking operation.
Fault Description