Lenze 8400 StateLine - Manual (Page 239)

Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
239
5 Motor control (MCTRL)
5.12 Monitoring
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5.12.2 Motor overload monitoring (I2xt)
The Inverter Drives 8400 are provided with a simple, sensorless, thermal I 2 xt motor monitoring of
self-ventilated standard motors which is based on a mathematical model.
• C00066 displays the calculated motor load in [%].
• If the calculated motor load reaches the motor load setting ( C00120 ):
• The error response set in C00606 will be carried out (Lenze setting: "Warning").
• The " oC6: I2xt motor overload " error message will be entered into the Logbook.
• The bMctrlI2xtOverload status output of the LS_DeviceMonitor system block will be set to
TRUE.
• A setting of C00606 = "0: No Reaction" deactivates the monitoring.

Stop!
I 2 xt motor monitoring does not provide full motor protection!
As the motor utilisation calculated in the thermal motor model is lost after mains
switching, for instance the following operating states cannot be detected correctly:
• Restarting (after mains switching) of a motor that is already very hot.
• Change of the cooling conditions (e.g. cooling air flow interrupted or too warm).
A full motor protection requires additional measures as e.g. the evaluation of
temperature sensors that are located directly in the winding or the use of thermal
contacts.
For the installation according to UL or UR, the safety instructions provided in the
hardware manual must be observed! Among other things, the activation of the motor
overload monitoring (I2xt) is required here.

Note!
From version 12.00.00 , the thermal motor load displayed in C00066 can be pre-
initialised when the device is connected to the mains, optionally using a fixed value or
the value used last at the time when the device was switched off. The desired
initialisation is selected in C00122 . In the Lenze setting of C00122 , the behaviour
remains unchanged (no initialisation).