13 thermal motor monitoring, 1 i2t monitoring, Function library – Lenze E82xVxxxKxxxxx User Manual
Page 357
Function library
Thermal motor monitoring
I
2
t monitoring
l
357
EDS82EV903 EN 3.0
10.13
Thermal motor monitoring
10.13.1
I
2
t monitoring
Description
With the I
2
t monitoring you can monitor self−ventilated three−phase AC motors thermally
without sensors.
)
Note!
The I
2
xt function is UL−approved.
ƒ
The I
2
xt monitoring is based on a mathematical model which calculates a
thermal motor utilisation from the motor currents measured.
ƒ
In UL−approved systems no additional protective measures for the motor are
required.
ƒ
However, the I
2
xt monitoring is no full motor protection, since other
influences on the motor utilisation cannot be detected, like changed cooling
conditions (e.g. cooling air flow interrupted or too warm).
ƒ
You can only obtain full motor protection if the motor is equipped with a
PTC thermistor or a thermal contact.
Codes for parameter setting
Code
Possible settings
IMPORTANT
No.
Name
Lenze Selection
C0120 I
2
t switch−off
0
0
= inactive
{1 %}
200 Reference: apparent motor
current (C0054)
Reference to active motor current
(C0056) possible, see C0310
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