Attention
For operation on two of the phase conductors of a 3–phase system, an isolating facility
for all poles must be provided.
10.10.3.4
Power Supply Power Boost and Derating
The power supply unit works with the static power reserve,
Power Boost
, as indicated in the U/I characteristic curve in the
following figure. At ambient temperatures of T
amb
< 40°C (104 °F),
Boost
output current (I
BOOST
) is available continuously.
At higher temperatures, it’s available for a few minutes. In the event of a secondary-side short circuit or overload, the output
current is limited to I
BOOST
. Therefore, the module does not power down but rather supplies a continuous output current, and
the secondary voltage is reduced until the short circuit is eliminated. The U/I characteristic curve with the power reserve
Power Boost ensures that both high inrush currents of capacitive loads and consumers with dc to dc converters in the Primary
circuit can be supplied.
To trip standard power circuit breakers magnetically and very quickly, power supplies must supply a multitude of nominal
current for a short period: I < I
N
, I > I
N
, and U < 0.9 x U
N
. (Refer to the section
for more information.)
Power Supply Output (U/I) Characteristic Curve
Item
Current
U
N
24 V
I
N
5 A
I
BOOST
7.5 A
SFB Technology
30 A
P
N
120 W
P
BOOST
180 W
At an ambient operating temperature of up to 40°C (104 °F), the unit continuously supplies Boost output current (I
BOOST
).
Nominal output current (I
N
) is supplied with ambient temperatures up to 60°C (140 °F). At higher temperatures (> 60°C), the
output power must be decreased by 2.5% per Kelvin temperature increase. At ambient operating temperatures above 70°C
(158 °F) or in the event of a thermal overload, the unit does not switch off. Reduce the output power enough to ensure the
protection of the device. Once the unit has cooled down, the output power is increased again.
PDM Power Distribution Modules
GEH-6855_Vol_II System Guide 411
Public Information
