g Industrial Systems
Cast Coil
Cast Coil Transformers
GE cast coil transformers are designed for indoor or
outdoor applications in the most demanding and
diverse environments. These transformers can be
applied in commercial installations such as pulp and
paper mills, chemical plants, coal mines and
anywhere that safe and dependable power are
important considerations. Cast coil transformers offer
some of the same installation advantages as ventilated
dry types (indoor installations do not require a liquid
confinement area, automatic fire extinguishing system
or fire vault, oil checking or replacing) while also
providing nearly the same protection against adverse
atmospheric conditions (the epoxy casting is
extremely inert and renders the windings impervious
to moisture, dirt and most corrosive elements) as
liquid filled units. The clearest advantage of cast
coils over ventilated dry and liquid filled coils is
mechanical strength. Properly designed and
manufactured cast coils are among the strongest coils
available. This makes cast coil transformers ideal for
applications such as impact loading, mobile
machinery and transit systems.
Cast Coils
“Cast Coils” are simply windings which have been
placed in molds and vacuum cast with an epoxy resin
compound. Beyond the definition, however, cast
windings are a highly engineered product requiring
specific expertise in the fields of electrical, material,
thermal and mechanical engineering. Equally
important is the process with which the casting
materials are measured, mixed, heated and vacuum
“poured” into the windings. Process control is
critical to insure that the coils are cast void free to
prevent partial discharges within the resin material
and to prevent cracking of the epoxy over a wide
range of ambient and operating temperatures.
HV coils may be designed as layer or barrel wound,
muti-section, strip disk or rectangular magnet wire
disk windings; depending on the voltage class, BIL
level or application of the transformer. Resin systems
are generally classified as unfilled or filled mixtures.
The unfilled resin contains a precise ratio of epoxy
resin, hardener, flexibilizer, accelerator and color.
The unfilled resin system requires precut glass fiber
materials to be placed under, between and over
winding sections to add strength to the epoxy resin.
The filled resin mixture contains a fairly large ratio
by weight of silicon flour (a fine powdery sand) to
add strength to the resin material.
operating conditions. Design tests and routine tests
developed through industry standards organizations
are a key measure of the dependability of a particular
design. For each transformer design family, design
and routine tests have been performed to assure that
the transformer will operate within its nameplate
rating for many years.
Cores
The transformer cores are constructed of non-aging,
high grade, grain oriented silicon steel laminations
with high magnetic permeability. Magnetic flux
densities are kept well below the saturation point.
Core laminations are free of burrs and stacked
without gaps. Mitered and step-lap construction
cores may be provided when specified. The core
clamping brackets are designed to provide an even
distribution of clamping forces to the core yokes and
legs. A copper core ground strap is provided.
Enclosure
The standard indoor enclosure is NEMA 1, Category
C construction. Enclosures are suitable for lifting,
jacking, rolling or skidding with provisions for lifting
from the transformer base. A stainless steel or copper
ground pad is provided on the LV side panel. The
enclosure has been sized and machined for the forced
air cooled rating. The enclosure paint finish is neat,
clean and highly resistant to corrosion. Metal
surfaces are thoroughly cleaned of scale, oil, grease,
rust and other foreign matter prior to painting. Unless
specified otherwise, paint color shall be ANSI 61
(light gray).
Forced Air Cooling
Provisions for future forced air (FFA) cooling is
inherent in all units rated 750 kVA and above. To
allow for the addition of fans, all current-carrying
components are designed to handle the increased
capacity. Provisions are also made for the future
addition of a fan control device.
The important criteria for solid cast winding design is
a reliable transformer life under normal or specified
Data subject to change without notice
9/9/99
g Industrial Systems
Cast Coil
Cast Coil Standard Features
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60 Hertz Operation
Vacuum Cast High Voltage Windings
80° or 115°C Average Winding Rise
Aluminum or Copper Windings
(2) 2 ½ % Full Capacity taps above and below Nominal
NEMA 1 Indoor Ventilated Enclosure
Removable front and rear panels
Provisions for lifting
Provisions for Future Fans
Core ground strap
ANSI ground pad on LV side
Vibration isolating pads
ANSI 61 paint finish
Cast Coil Basic Impulse Ratings
Nominal
System
Voltage
kV
1.2
2.5
5.0
8.7
15.0
Standard
BIL kV
Option
BIL kV
10
45
60
75
95
30
60
75
95
110
Table 1
Cast Coil Sound Levels: (dB)
Cast Coil Accessories Options
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NEMA 3R Outdoor Enclosure
Space Heaters
Thermostat for Space Heaters
120/240 V Fans for 133% FA kVA
Temperature Monitor/Fan Controller
Filters over Ventilation Openings
Copper Flange to Flange Ground Bus
Future Fan Wiring and Control
Equivalent
Two Winding
Base kVA
500
750
1000
1500
2000
2500
3000
SelfCooled
dB
60
64
64
65
66
68
68
FanCooled
dB
N/A
67
68
69
71
71
73
Table 2
Special Design or Application
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Low Loss Designs
Rectifier Transformer Designs
Special Ambient Designs
High Overload Capacity Designs
Special/Low Sound Level Designs
50 Hertz Designs
Seismic Zone IV Designs
Five-Legged Core Designs
Series/Parallel Windings
HV Wye Connection to LV Delta
Electrostatic Shield
Retrofit to Specific Dimensions
K-Factor Ratings
Special Paint
Data subject to change without notice
9/9/99
g Industrial Systems
Cast Coil
Cast Coil Case Outline
Enclosure Dimensions
kVA
D
A
HV
ATC
B
H
A
LV
ATC
500
750
1000
1500
2000
2500
3000
Height
Inches
90
90
90
100
100
100
110
Width
Inches
84
86
88
96
108
108
108
Depth
Inches
54
56
58
60
60
64
64
Weight
lb.
7000
8500
10500
12500
15500
17500
20000
C
W
HV Air Filled Terminal Compartment (ATC)
BIL
60
95
110
Dimension
A
B
A=H
15
A=H
22
A=H
25
Weight
250
400
450
LV Air Filled Terminal Compartment (ATC)
Cables/Phase
1-4
5-8
Dimension
A
C
A=H 15
A=H 22
Weight
250
400
Air Terminal Compartments
Enclosure Dimensions
1.
2.
3.
4.
5.
1.
Dimensions are approximate for kVA, 80°C Rise, 15
kV Class, 95 kv BIL and usual service conditions.
Width dimensions may decrease slightly for 5 kV Class
units and/or 115 °C rise units.
Height and depth dimensions may increase 4 to 8 inches
each for outdoor NEMA 3R enclosures.
Dimensions may vary with special requirements.
Dimensions and weights are subject to change without
notice and should not be used for construction purposes.
Terminal boxes can be supplied on the primary or
secondary side of the transformer.
2. HV terminal boxes are suitable for single or loop feed.
3. Bolted-on end panel gives easy access to the cable
fittings.
4. Incoming line cables can enter the top or bottom of the
terminal box and can be connected for up to 8 cables
per phase.
5. The standard method for cable connections is with
clamp type terminals (#2-4/0 AWG, 250-500 MCM or
600-1000 MCM).
6. NEMA two hole lugs are available upon request.
7. GE Tranquell Intermediate, Distribution, and Station
type arresters are available when specified.
8. Dimensions and weights are subject to change without
notice and should not be used for construction purposes.
ALL DIMENSIONS ARE APPROXIMATE
Data subject to change without notice
9/9/99
g Industrial Systems
Cast Coil
Data subject to change without notice
9/9/99