Siemens 6SE7086-4AH85-1BA0 operating instructions Protection against moisture condensation

01.03 Assembly

2.4Notes on materials

Cooling-water installations with components of copper or copper compounds must be avoided and are only possible if special measures are taken, e.g. closed cooling circuit, full-filtering system (i.e. CU ions are filtered out), additives to the water (e.g. products of "Schilling Chemie GmbH“, P.O.Box 1136, D-71687 Freiberg, Tel. +49 7141-703-0).

The hose connecting nipples on the heat-sink side must be made of stainless steel or thick aluminium. The connecting nipples must never be made of brass or copper.

PVC hoses are unsuitable if anti-freeze is used.

Rigid-PVC pipes are suitable for the anti-freeze agents named in Section 2.3.2.

It must be ensured that the water circuit is completely free of zinc.

The following is especially important if anti-freeze agents are used:

Zinc breaks down all inhibitors which have a glycol basis.

Never use galvanized pipes!

If normal iron pipes or components made of grey cast iron are used for the piping (e.g. motor housing), a separate circuit with water-to-water heat exchangers is to be used for the units.

If a heat exchanger made of CuNi 90/10 is used, the water conductivity and the installation notes (hose) must be borne in mind.

2.5Protection against moisture condensation

Special measures are necessary for protection against moisture condensation.

Moisture condensation occurs when the inlet temperature of the cooling water is considerably lower than the room temperature (air temperature). Depending on the relative humidity Ф of the air, the temperature difference between the cooling water and the air can be higher or lower. The temperature at which water vapour in the air becomes saturated and dew begins to form is called the dew point.

In the following table, the dew points (in °C) for an atmospheric pressure of 1 bar (corresponding to an altitude of approx. 0 to 500 m) are given. If the cooling-water temperature is below these levels, moisture condensation can be expected, i.e. the cooling-water temperature must always be higher than the dew-point temperature.

T Raum	Ф=20%	Ф=30%	Ф=40%	Ф=50%	Ф=60%	Ф=70%	Ф=80%	Ф=85%	Ф=90%	Ф=95%	Ф=100%
°C
10	<0	<0	<0	0,2	2,7	4,8	6,7	7,6	8,4	9,2	10
20	<0	2	6	9,3	12	14,3	16,4	17,4	18,3	19,1	20
25	0,6	6,3	10,5	13,8	16,7	19,1	21,2	22,2	23,2	24,1	24,9
30	4,7	10,5	14,9	18,4	21,3	23,8	26,1	27,1	28,1	29	29,9
35	8,7	14,8	19,3	22,9	26	28,6	30,9	32	33	34	34,9
38	11,1	17,4	22	25,7	28,8	31,5	33,8	34,9	36	36,9	37,9
40	12,8	19,1	23,7	27,5	30,6	33,4	35,8	36,9	37,9	38,9	39,9
45	16,8	23,3	28,2	32	35,3	38,1	40,6	41,8	42,9	43,9	44,9
50	20,8	27,5	32,6	36,6	40	42,9	45,5	46,6	47,8	48,9	49,9

Dew-point temperature as a function of the relative humidity Ф and the room temperature for an installation altitude of 0 m.

Siemens AG 6SE7086-4AH85-1BA0	ENGLISH	2-5
Common rectifier and rectifier/regenerating units with water cooling	Supplement to the operating instructions