The derating curve
indicated the maximum current that can permanently and simultaneously flow
through all
connections if the component is exposed to ambient temperatures below its
upper limit temperature.
The upper limit temperature
of a component is determined by the materials. The maximum temperature
is
calculated from the ambient temperature and from heating due to current
loading, it must not exceed the upper limit temperature of the component.
The derating of a component is not a constant value, but decreases hand-in
hand with the increase in component ambient temperature. Furthermore,
current loading capacity is dependent upon geometry, the materials employed,
the number of poles and conductor.
Since it is not advisable to
use Heavy Duty connectors at their loading limits, the base curve is reduced.
If the loading currents are reduced to 80%, then this produces the reduced
base curve in relation to the various
connectors and measurement uncertainties at which temperature measurements
are taken into account. Experience shows that the reduced base curve
is successful popular application.
NB: Only the reduced base curve
is reproduced on the following derating curves for inserts. |
