Siemens SINAMICS S120 Manual page 774

Cooling circuit and coolant properties
13.1 Cooling circuit requirements
The maximum permissible system pressure is 600 kPa.
If a pump that is capable of exceeding this maximum permissible system pressure is used,
the customer must take steps (e.g. safety valve p ≤ 600 kPa, pressure control, or similar) to
ensure that the maximum pressure limit is not exceeded.
Permissible pressure difference
The maximum permissible pressure difference for a heat sink is 200 kPa. Higher pressure
differences significantly increase the risk of cavitation and abrasion. The lowest possible
differential pressure between the coolant in the supply and return lines should be selected to
allow pumps with a flat characteristic to be used.
Figure 13-2 Pressure difference as a function of volumetric flow
Pressure difference and pressure drop when using coolant mixtures
If a mixture of Antifrogen N and H
calculated according to the mixing ratio. The following table specifies the pressure drop
across components at different coolant temperatures for a coolant with mixing ratio 45 %
Antifrogen N.
Table 13- 1 Pressure drop at different coolant temperatures for Antifrogen N/H
dV/dt H O dP H
2
[l/min] [kPa]
8 70
774
O dP Antifrogen N
2
0 °C
[kPa]
121
O is used as a coolant, the rated pressure must be
2
O: 45 %
2
dP Antifrogen N
20 °C
[kPa]
97
Manual, (GH2), 07/2016, 6SL3097-4AC00-0BP8
dP Antifrogen N dP Antifrogen N
45 °C
[kPa]
81
Booksize Power Units
50 °C
[kPa]
78