Lenze E94AxPExxxx - Manual (Page 263)

Lenze · 9400 Servo PLC· Reference manual · DMS 4.0 EN · 11/2013 · TD05/06
263
6 Motor interface
6.9 Monitoring
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6.9.2 Motor monitoring (I
2
xt)
The "Servo Drives 9400" are provided with an extended, sensorless thermal I 2 xt motor monitoring
function which is based on a mathematical model that calculates a thermal motor utilisation from
the detected motor currents.
• The calculation considers the speed dependency of the torque (difference between standstill
torque and rated torque).
• C00066 indicates the calculated motor utilisation in [%].
• If the motor utilisation exceeds the advance warning threshold set n C00127 , the error message
"I2t motor overload OC8" is output and the response (default setting: "Warning") set in C00606
is activated..
• If the switch-off threshold set in C00120 is exceeded, the error message "I2t motor overload
OC6" is output and the "Fault" response is activated.
• From software version V5.0:
After mains switching, the thermal model of the I²xt motor monitoring is initialised with the
starting value initialised in C01197 .

Stop!
The I
2
xt motor monitoring function is no full motor protection!
Since the motor utilisation calculated in the thermal model gets lost after mains
switching, the following operating states cannot be determined 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).
Full motor protection requires additional measures such as the evaluation of
temperature sensors that are located directly in the winding or the use of thermal
contacts.