SOLARDRIVE
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2.6.8.
Motor Thermal Protection Menu
2.6.8.1. Overview
The Motor Thermal Protection function protects the motor against overloads.
It is also possible to set the heatsink temperature to make cooling fans start operating (this function is not
available for all models).
For each programmable motor, thermal protection can be configured in 3 modes, which can be selected with
parameter
C265
, depending on the cooling system being used (configuration modes 1, 2 and 3):
Value
Descr.
IEC 34-6
Compliance
Description
0:NO
[Disable]
-
The Motor Thermal Protection function is disabled.
1:YES
[No Derating]
IC410
The Motor Thermal Protection function is active with trip current
I*t
independent of operating speed (No derating);
2:YES A
[Forced
Cooling]
IC411
The Motor Thermal Protection function is active with trip current
I*t
depending on operating speed, with fan-cooled motor de-rating (Forced
Cooling);
3:YES B
[Fan on Shaft]
IC416
The Motor Thermal Protection function is active; trip current
I*t
depends
on operating speed and de-rating is suitable for motors having a fan
keyed to the shaft (Fan on Shaft) (factory setting).
When
C265
=1, 2 and 3, the motor thermal model is considered. The heating of a motor is proportional to the
square of the current flowing (I
o
2
). The Motor overheated alarm (
A075
) will trip after the time “t” computed
based on the motor thermal model is over.
The alarm can be reset only after a given time depending on the thermal constant (
C267
) of the motor, thus
allowing for the correct cooling of the motor.
Figure 9: Trip current drop depending on speed values
