ZIEHL-ABEGG Ucontrol PXDM10A - 4.8 Power Decrease for Ambient Temperatures Over 40° C (Derating)

Handbook Ucontrol type-lines PXDM Date 06/04
TBL02_55-GB06/04 Part.-No. 00153239-GB
Page 13 / 105
4.8 Power decrease for ambient temperatures over 40° C (Derating)
The unit´s maximum permissible ambient temperature is 40° C, up to that temperature a load of the quoted rated current
is possible. The removal of heat in the unit due to power dissipation is dependent on the ambient temperature, so the
maximum load has to be reduced if the ambient temperature is higher than 40° C!
¨ The median (measured 24 h) has to be 5° C below the max. ambient temperature.
¨ Pay attention of the unit´s power dissipation and their possible effects on the ambient temperature if the unit
is mounted in a switch cabinet (F General description: Technical data)!
Determinating the max. permanent current depending on the ambient temperature:
Nenn
i
K
i ·D··-= )
1
04,01(
max
J
=DJ ambient temperature – max. permissible ambient
temperature in Kelvin (K)
Example:
Max. permissible ambient temperature
(operating instructions): 40° C
Max. possible ambient temperature: 50° C
Rated current controller e.g. PXDM15: 15 A
=DJ ambient temperature = 50° C – 40° C = 10 K
AAK
K
i 915)10
1
04,01(
max
=···-=
100 %
max. Dauerstrom [A]
max. permanent current [A]
max. Umgebungstemperatur [°C]
max. ambient temperature [C°]
40 45 50 55
80 %
60 %
40 %
20 %
Regelgeräte Bemessungsstrom
Controller rated current