2 motor load monitoring (i2xt), Motor load monitoring (i2xt), 5motor control (mctrl) – Lenze E84DSxxx User Manual
Page 181: Stop
Lenze · 8400 protec StateLine · Reference manual · DMS 4.2 EN · 03/2013 · TD05
181
5
Motor control (MCTRL)
5.10
Monitoring
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5.10.2
Motor load 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.
•
displays the calculated motor load in [%].
• If the calculated motor load reaches the motor load setting (
• The error response set in
will be carried out (Lenze setting: "Warning").
• The "
" error message will be entered into the Logbook.
• The bMctrlI2xtOverload status output of the
system block will be set to
TRUE.
• A setting of
= "0: No Reaction" deactivates the monitoring.
Adjustment of the motor utilisation meter
The motor utilisation meter for indicating the motor load in
begins to count when the
apparent motor current (
) is greater than the motor overload setting (
).
is to be set as follows:
• If you reduce
starting from the calculated value, the motor utilisation meter will already
be counted up before the rated overload threshold is reached.
• If you increase
starting from the calculated value, the motor utilisation meter will not
be counted up until the rated overload threshold is reached.
Stop!
The I
2
xt motor monitoring does not present 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 measured 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.
I
r
: Rated motor current (see nameplate of motor)
I
N
: Rated controller current at a switching frequency of f = 8 kHz
C00120
I
r
I
N
-----
100%
⋅
=