Protection Against Condensation - Siemens Vector Control Operating Instructions Manual

05.2006
13.1.4

Protection against condensation

φ φ
Room = =
temp. 20 % 30 %
°C
10 < 0 < 0
20 < 0 2
25 0.6 6.3
30 4.7 10.5
35 8.7 14.8
38 11.1 17.4
40 12.8 19.1
45 16.8 23.3
50 20.8 27.5
Siemens AG 6SE7087-2JD60
SIMOVERT MASTERDRIVES
Special measures are necessary to prevent condensation.
Condensation occurs when the cooling water inlet temperature is
considerably lower than the room temperature (air temperature). The
permissible temperature difference between cooling water and air
varies according to the relative humidity φ of the room air. The
temperature at which moist air will deposit droplets of water is called
the dew point.
The following table lists the dew points (in °C) for an atmospheric
pressure of
1 bar (≈ height 0 to 500 m above sea level). If the cooling water
temperature is lower than the value given, condensation must be
expected, i.e. the cooling water temperture must always be ≥ dew point.
φ φ φ
= = =
40 % 50 % 60 %
< 0 0.2 2.7
6 9.3 12
10.5 13.8 16.7
14.9 18.4 21.3
19.3 22.9 26
22 25.7 28.8
23.7 27.5 30.6
28.2 32 35.3
32.6 36.6 40
Table 13-11 Dew point temperature as a function of relative humidity
temperature at an altitude of 0 m above sea level
The dew point also depends on the absolute pressure, i.e. on altitude.
The dew points for low atmospheric pressures lie below the value for
sea level, and it is therefore always sufficient to plan the cooling water
supply temperature for an altitude of 0 m.
Operating Instructions
φ φ φ
= = =
70 % 80 % 85 %
4.8 6.7 7.6
14.3 16.4 17.4
19.1 21.2 22.2
23.8 26.1 27.1
28.6 30.9 32
31.5 33.8 34.9
33.4 35.8 36.9
38.1 40.6 41.8
42.9 45.5 46.6
Technical Data
φ φ φ
= = =
90 % 95 % 100 %
8.4 9.2 10
18.3 19.1 20
23.2 24.1 24.9
28.1 29 29.9
33 34 34.9
36 36.9 37.9
37.9 38.9 39.9
42.9 43.9 44.9
47.8 48.9 49.9
φ
and room
13-21