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Rules for a correct installation
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Some indications,in order
to get the best service efficiency, preservation and
service of the transformet, shall be taken into
consideration: |
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The ambient temperature of the
transformer cell shall not exceed the one set forth
by CEI 14-8/IEC 726 standarts, so it has not to be
over 40 °C, also when transformer is in
service.Particular working conditions or ambient
temperature shall be notified to the constructor,who
will adjust the proper rating of the transformer
according to the overloads.
- The transformer cell shall be opportunely ventilated to enable the complete dissipation of the losses.
- The transformer- even if provided with housing-shall be installed indoors, except the case where particular requests
shall be discussed with the manufacturer.
- The transformer shall be installed in places where the maximum sea level altitude is 1000 metres; otherwise it is necessary to reduce
the rating of the transformer according to IEC standarts.
- The transformer, with or without housing, shall be located so that is possible to reach all ,its
important parts (LV terminals,HV terminals,HV tapping,windings with thermometric sensors).
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Safety Rules |
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For a standart service of transformer, in order to observe safety both for the users and the places of the installation,
some important requirements shall be taken into consideration: |
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before to carry out any operation on the transformer, and/or on its parts, check that it has been disconnected from the network and
that it has been grounded.
- IP00 transformer shall be protected againts direct contacts.
- the protective housing containing the transformer, if provided with cooling grids, shall be placed at least 300 mm away from the room
walls;this distance may vary only after that S.E.A. technical department workout the data provided by the customers of the place of
installation (this to avoid an until air change to the transformer with a consequent overheating of it).
- In accordiance with prescribed from CEI 11-18 regulations, the transformer has to be placed at the following distances from an even wall.
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Aeration of the place of installation |
The transformer cell must be large enough to ensure that the maximum design temperature will be never exceeded.
The transformer must be placed in such a way that all the heat radiating surfaces are top-down continuously under ventilated
from either a natural or forced airflow.
For installation at altitudes lover than 1000 metres above sea level and a room temperature of 40°C, an air renewal rate of
about 4,5 m3/minute for each kW of loss is necessary.
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Insulation level
Isolationklasse
[kV]
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Distance to concrete wall
Abstand von volle Wand
[mm]
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Distance to grid-wall
Abstand von
[mm]
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7,2 |
90 |
300 |
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12 |
120 |
300 |
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17,5 |
160 |
300 |
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24 |
220 |
300 |
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36 |
320 |
320 |
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Click to Enlarge |
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Example:
H= distance between the middle of the vent window and middle of the transformer expressed in metres.
S= section in m of the window
W= losses to be dissipated (in kW)
t2-t1= thermal need between inlet and outlet of the air considering that it enetrs from the bottom,
through a duct with a section equal to S.
For a transformer with W=16kW, t2-t1=15°C, H=3,4m,tha abacus provide a value of S=1,5m.
Join with a straight line the axis point W (16kW) with the one of t2-t1 selected axis (15°C);from the intersection of the same one with X axis, draw a straight line to the available H value (3,4m).
The S axis is to be forms in correspondence with the necessary value for the opening of the entrance and of the exit of the air.
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