Lenze 931E/K Small Drives Control - Manual (Page 121)

Troubleshooting and fault elimination
Error monitorings in the 931E/K
Overcurrent and short−circuit monitoring
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121 SW−HB 13.0002−EN 4.1
9 Troubleshooting and fault elimination
9.1 Error monitorings in the 931E/K
The 931E/K servo positioning controller is equipped with a comprehensive sensor
technology that monitors the trouble−free functioning of the controller, the power stage,
the motor and the communication with the outside world. All errors that occur will be
saved in the internal history buffer.
The most important monitoring functions will be described in the following sections.
)
Note!
An easy−to−use error management allows you to adapt the controller response
to the individual errors, see the chapter "Error management". (
¶ 132)
9.1.1 Overcurrent and short−circuit monitoring
ƒ Overcurrent and short−circuit monitoring:
The overcurrent and short−circuit monitoring will respond, if the DC−bus current
exceeds twice the maximum controller current. The monitoring detects short circuits
between two motor phases and short circuits at the motor output terminals against
the positive reference potential of the DC bus. If the error monitoring detects an
overcurrent, the power stage will be switched off immediately to ensure the
short−circuit strength of the controller.
ƒ I 2 T current monitoring with warning for the controller:
The 931E/K servo positioning controller is equipped with an I 2 t−monitoring to limit the
average power loss in the power stage. Since the power loss in the power electronics
and in the motor will in the worst case increase square−law with the flowing current,
the squared current value will be used to measure the power loss. When reaching 80 %
of the maximum integrated measurand, a warning (parameterisable) will be activated.
When reaching 100 %, the maximum current will be limited to the rated current.
ƒ Current measurement check and offset adjustment when switching on the power
stage:
When the power stage is switched on, an automatic offset adjustment of the current
measurement will be started. If the offset adjustment is not within the permissible
tolerances, an error will be generated.