Siemens SINAMICS S120 Equipment Manual page 243

Pressure
The maximum permissible system pressure is 600 kPa. The lowest possible pressure should
be selected to allow use of pumps with a flat characteristic.
Maximum permissible differential pressure for a heat sink: 150 kPa (is applicable for water
as coolant).
The layout must be selected such that the total length of feed and discharge line is equal for
each SINAMICS device or motor.
It is not permissible to use water cooling systems with devices or devices and motors
connected in series as the increased volumetric flow increases the risk of cavitation and
abrasion.
Coolant temperature
To prevent condensation, the coolant temperature should be controlled depending on the
ambient temperature and the air humidity. Condensation on the device is not permissible.
Coolant temperature ranges:
● 0 ... 38 °C without derating
● >38 ... 43 °C see derating data
Operation with a coolant temperature between 0° C and 5° C is only permitted with
antifreeze. Operation below 0° C is also not permitted with antifreeze.
Volume flow monitoring
The devices are equipped with volume flow monitoring. If the average output flow is less
than the rated flow, then the volume flow may also be correspondingly lower. If occasionally
overloads occur during operation with the average output flow that are higher than the
average output flow, then the rated volume flow must also be provided.
It must be ensured that the volume flow is never zero.
Water-cooled chassis power units for common cooling circuits
Manual, 08/2017, 6SL3097-4AM10-0BP0
Cooling circuit, coolant properties and protection against condensation
9.1 Cooling circuits
243