3.7.2
Operating principle of the re-cooling unit
The re-cooling unit dissipates the heat loss from the drive. The deionized water in the internal
water circuit absorbs the heat of the drive power unit which is to be dissipated, and is pumped
to the heat exchanger by a maintenance-free circulating pump. The warm deionized water is
cooled by the external raw water circuit and pumped back to the drive.
Two pipes are installed in the drive. The cold water of the re-cooling unit flows in one of the
pipes, and is heated by the losses and flows back to the re-cooling unit through the other pipe.
For additional information, refer to the operating instructions of the re-cooling unit.
3.7.3
The internal deionized water circuit
The internal water circuit is filled with deionized water (deionized, fully-desalinated water). The
conductivity of the cooling water must be ≤ 1 µS/cm in operation.
NOTICE
Inadmissible additives in the deionized water
Inadmissible additives in the deionized water can cause the cooling system to fail. This could
damage the drive.
● Use only deionized water that corresponds to the specifications. The specification of the
deionized water can be found in the documentation for the re-cooling unit.
● The level of the deionized water expansion tank is monitored for any water leakages and the
pump motor circuit breakers are also monitored.
● The pressure of the deionized water is displayed on a manometer.
● The deionized water temperature is measured. The value is used for controlling the three-
way valve
● If one of the monitoring devices responds, a signal is output or the re-cooling unit and drive
are switched off.
Deionized water requirements
Table 3-1
Deionized water requirements
Value
Conductivity during filling
< 10 μS/cm
Evaporation residue
< 20 mg/l
pH value
5 to 9
Description
3.7 Re-cooling unit
SINAMICS PERFECT HARMONY GH150 6SL38253AE412AA1-Z
Operating Instructions Rev.201910281231 EXAMPLE
35
