6 Cooling System
6.1 Installation of water-cooled units
Water-cooled
drive converters
are operated in continuous operation with lower tempera-
ture than air-cooled inverters. This has positive effects on lifetime-relevant components
such as fan and DC link circuit capacitors and power modules (IGBT). Also the temper-
ature dependent switching losses are positively effected. The use of water-cooled KEB
COMBIVERT
drive converters
is offered in the drive technology, because there are pro-
cess-caused coolants available with some applications. The following instructions must
be observed absolutely when this units are used.
6.1.1 Heat sink and operating pressure
Design system
Material (voltage)
max. operating pressure
Connecting duct
Extrusion casting heat sink
Aluminium (-1.67 V)
10 bar
0000650-G140
The heat sinks are sealed with sealing rings and posses a surface protection (anodized)
even in the ducts.
ATTENTION
Maximum operating pressure
The heat sink is permitted for a pressure or leak test upto 2-fold, maxi-
mum operating pressure. An UL acceptance with 5-fold, maximum oper-
ating pressure was executed. Pay attention to the guidelines 97/23/EC
of pressure units.
6.1.2 Materials in the cooling circuit
For the screw connections and also for the metallic articles in the cooling circuit which
are in contact with the coolant (electrolyte) a material is to be selected, which forms a
small voltage difference to the heat sink in order to avoid contact corrosion and/or pitting
corrosion (electro-chemical voltage series, see table). An aluminum screw connection
or ZnNi coated steel screw connection is recommended. Other materials must be exam-
ined in each case before employment. The specific case of application must be checked
by the customer in tuning of the complete cooling circuit and must be classified accord
-
ing to the used materials. With hoses and seals take care that halogen-free materials
are used.
A liability for occuring damages by wrongly used materials and from this resulting corro-
sion cannot be taken over !
Material
Generated Ion
Standard
potential
Material
Generated Ion
Standard
potential
Lithium
Li
+
-3.04 V
Cobald
Co
2+
-0.28 V
Potassium
K
+
-2.93 V
Nickel
Ni
2+
-0.25 V
Calcium
Ca
2+
-2.87 V
Tin
Sn
2+
-0.14 V
Sodium
Na
+
-2.71 V
Lead
Pb
3+
-0.13 V
Magnesium
Mg
2+
-2.38V
Iron
Fe
3+
-0.037 V
Titan
Ti
2+
-1.75 V
Hydrogen
2H
+
0.00 V
continued on the next page
55
COOLING SySTEM
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