Lenze 9400 - Manual (Page 215)

Lenze · Servo-Inverter 9400 HighLine · Reference manual · DMS 10.0 EN · 11/2013 · TD05/06
215
5 Motor interface
5.9 Monitoring
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5.9.2 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 V11.0:
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).
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.

Note!
The result of the calculated thermal motor utilisation may be too low for quick
traversing cycles (so-called pick-and-place applications) which include acceleration and
deceleration times of less than 100 ms during overload operation of the motor (often
used: linear motor).