5
vacon • 56 Installation
Local contacts: http://drives.danfoss.com/danfoss-drives/local-contacts/
Specification: Process water
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 AC drives
are. The connections between these two are made on site. In order to minimize the pressure drops,
the pipings must 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 must 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 AC drive inlet. Open the bypass valve and shut the
valves to the AC drive when cleaning and airing the system. On commissioning the system, the
bypass valve must be closed and the valves to the AC drives opened.
Below you will find a simplified example of the cooling system as well as an example of the
connections between the AC drives and the cooling system.
Table 18. Process water specification
Quality Unit Value
pH 6…9
Water hardness °dH <20
Electrical conductivity μS/cm <100
Chlorides (Cl)
*
*. 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.
mg/l <100
Iron (Fe) mg/l <0.5
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