Siemens GEAFOL Operating Instructions Manual page 8

GEAFOL- / CARECO-Cast-resin Transformer/ Operating Instructions
Description
1 Low-voltage terminals
2 Lifting lugs
3 Lashing lugs
4 High-voltage terminals
5 Delta connection
6 Grounding screw
7 Lower core frame
8 Wheels, can be turned 90°
9 Pulling lugs
10 High-voltage tappings
11 (these may also be on the low-
voltage terminal side)
12 Casted high-voltage winding
13 Connection for temperature
monitoring system
14 Upper core frame
15 Low-voltage winding
Core
Only grain-oriented, cold-rolled sheets insulated on both
sides are used for the iron core. The leg and yoke cross-sec-
tions are staggered with different lamination widths. The
outer legs have miter joints. Legs and yokes are connected
by 45° cuts, and the middle leg with a pointed miter joint
at the yoke junction.
Windings
The high-voltage coils are made of aluminum or copper
foils and high-quality insulating films. Each phase winding
is formed from several separate coils connected in series;
these are encapsulated in resin under vacuum. The
winding ends and tappings are routed to threaded bushes
and are encapsulated with the remainder of the winding.
The low-voltage coils are made of aluminum/copper strips
and resin-impregnated insulating film (prepreg).
Insulation
The insulation structure is dimensioned on the basis of the
impulse voltage distribution. It ensures freedom from par-
tial discharge up to twice the rated voltage, as well as ther-
mal and mechanical strength.
Supports
A clamping arrangement designed specifically for the char-
acteristics of the strip/foil windings and the flexible bracing
of the coils ensure both high short-circuit strength and a
very low noise level.
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