Vacon NX User Manual page 52

vacon • 50
Specification: Process water
Electrical conductivity
*. The allowed concentration of chloride ions (Cl–): <1000 ppm at 20 °C, < 300 ppm at 50
°C and < 100 ppm at 80 °C; the values are given as guidance to reduce the corrosion risk
on stainless steel. The values are valid for pH=7. Lower pH value increases the risk.
The design temperature of the cooling agent entering the drive module(s) is 35 °C. While circulating
inside the cooling element, the liquid transfers the heat produced by the power semiconductors
(and the capacitors). The design temperature rise of the cooling agent during the circulation is less
than 5 °C. Typically, 95% of the power losses is dissipated in the liquid. We advise you to equip the
cooling agent circulation with temperature supervision.
The heat exchanging equipment can be located outside the electrical room in which the frequency
converters are. The connections between these two are made on site. In order to minimize the
pressure drops, the pipings shall be made as straight as possible. We further recommend that a
regulating valve equipped with a measurement point is mounted. This makes the measurement and
regulation of liquid circulation possible in the commissioning phase.
In order to prevent dirt particles from accumulating in the connections and thus gradually
weakening the cooling effect, installation of filters is also recommended.
The highest point of the piping must be equipped with either an automatic or a manual venting
device. The material of the piping must comply with at least AISI 304 (AISI 316 is recommended).
Prior to the actual connection of the pipes, the bores shall be cleaned thoroughly. If cleaning with
water is not possible, although recommended, pressured air must be used to remove all loose
particles and dust.
To facilitate the cleaning and venting of the coolant circulation, we recommend you to install a
bypass valve in the main line and valves at each frequency converter inlet. Open the bypass valve
and shut the valves to the frequency converter when cleaning and airing the system. On
commissioning the system, the bypass valve shall be closed and the valves to the converters
opened.
Below you will find a simplified example of the cooling system as well as an example of the
connections between the frequency converters and the cooling system.
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: info@clrwtr.com
5
Table 14. Process water specification
Quality
pH
Water hardness
*
Chlorides (Cl)
Iron (Fe)
Unit
°dH
μS/cm
mg/l
mg/l
INSTALLATION
Value
6...9
<20
<100
<100
<0.5