c.1.4 Special requirements for open and half-open cooling systems:Problem SolutionImpurities Mechanical impurities in half-open cooling systems can be counteracted when ap-propriate water filters are used.Salt concentration The salt content can increase through evaporation at half-open systems. Thus thewater is more corrosive. Adding of fresh water and removing of process waterworks against.Algae and myxobac-teriaAlgae and myxobacteria can arise caused by increased water temperature andcontact with atmospheric oxygen. The algae and myxobacteria clog the filters andobstruct the water-flow. Biocide containing additives can avoid this. Especially atlonger OFF periods of the cooling circuit preventive maintenance is necessary.Organic materials The contamination with organic materials must be kept as small as possible, be-cause separate slime can be caused by this.Table 8: Special requirements for open and half-open cooling systems:ATTENTION Damages at the unit► Damages at the unit which are caused by clogged, corroded liquidheat sinks or other obvious operating errors, leads to the loss of thewarranty claims.c.1.5 Coolant flow temperatureThe coolant flow temperature is depending on the unit size and is specified in thetechnical data.Flow temperatureThe flow temperature should be selected depending on the volume flow byway that the heat sink temperature at rated operation is always 10 K belowthe overtemperature level. This avoids sporadic shutdown.c.1.6 Moisture condensationDue to high air humidity and high temperatures it can lead to moisture condensation.Moisture condensation is dangerous for the drive converter, because the drive convertercan be destroyed by any occuring short-circuits.ATTENTION Moisture condensation► The user must ensure that any moisture condensation is avoided!73ANNex - cOOLING SySTeM
