38 • vacon
INSTALLATION
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5
5.2
Cooling
Instead of using air for cooling, Vacon NX Liquid-Cooled drives are cooled with liquid. The liquid circulation
of the drive is usually connected to a heat-exchanger (liquid-liquid/liquid-air) which cools down the liquid
circulating in the cooling elements of the drive. Because the cooling elements are made of aluminium, the
cooling agents allowed to be used are drinking water, demineralized water or a mixture of water and
glycol. In a closed circulation system, the following figures are recommended reference values. To avoid
electrochemical corrosion, we furthermore recommend to add an inhibitor (e.g. Ferrolix 332/Henkel or
Cortec VpCI-649) in the cooling agent.
The heat-exchanger delivered by Vacon (HXL) consists of stainless steel materials. The good corrosion
performance of stainless steel in district water systems is utilized and no disadvantage of divergent metal
filler is included. Nevertheless, some precautions must be taken to reduce the corrosion risk on the
stainless steel in high chloride waters, see Table 5-5. We recommend to use a Vacon HXL heat exchanger
whenever possible.
Note: If no heat-exchanger is used, actions must be taken to avoid electrochemical corrosion. Specifically
no brass or copper elements may be used in the liquid circulation of the drive.
Specification: Drinking water
The attached table gives the chemical requirements for drinking water provided for by the Finnish Ministry
of Social Affairs and Health. These values are indicative.
Quality
Unit
Value
Acrylamide µg/l
0.10
Antimony µg/l
5.0
Arsenic µg/l
10
Benzene µg/l
1.0
Benzopyrene µg/l
0.010
Boron mg/l
1.0
Bromate µg/l
10
Cadmium µg/l
5.0
Chromium µg/l
50
Copper mg/l
2.0
Cyanides µg/l
50
1,2-Dichloroethane µg/l 3.0
Epichlorohydrin µg/l
0.10
Fluoride mg/l
1.5
Lead µg/l
10
Mercury µg/l
1.0
Nickel µg/l
20
Quality
Unit
Value
Nitrate (NO
3
-
) mg/l
50
Nitrate-Nitrogen (NO
3
-
N)
mg/l
11.0
Nitrite (NO
2
-
) mg/l
0.5
Nitrite-Nitrogen (NO
2
-N) mg/l
0.15
Bactericides µg/l
0.10
Bactericides, total
µg/l
0.50
Polynuclear aromatic
hydrocarbons
µg/l 0.10
Selenium µg/l
10
Tetrachloroethylene and
trichloroethylene tot.
µg/l 10
Trihalomethanes tot.
µg/l
100
Vinyl chloride
µg/l
0.50
Chlorophenols total
µg/l
10
Table 5-3. Drinking water chemical specification
