User's Manual

Installation / connection
4.1 Installation
M200D AS-Interface Basic
48 Manual, 03/2009, A5E01668085-01
4.1.2 Derating
What is derating?
Derating allows devices to be used even in severe operating conditions by selectively
restricting the output capacity.
Derating factors
When M200D AS-i motor starters are operated under harsh conditions, the following factors
must be taken into account:
● Ambient temperature T
u
:
– The ambient temperature T
u
is the temperature of the air surrounding the motor starter
housing.
The lower the maximum ambient temperature T
u
, the higher the current load on the
motor starter can be.
– The installation position affects how quickly the motor starter cools.
● Absolute current load:
– The lower the current flowing through the motor starter, the lower the power loss
(= heat) inside the device. If slight self-heating occurs, the ambient temperature T
u
can
be higher.
– In the case of soft starters in which the soft start function has been deactivated, the
maximum permissible rated operating current I
e
is restricted to 9 A (≡ electronic direct
starter; sDSte).