Au TO / i S O l AT i O N T R A N S F O R M E R S
Step-D ow n, St e p- Up and I so l ation Transformers
Auto/Isolation Transformers
Isolation Transformers
have two (2) separate windings with an elec-
trostatic shield between them to provide complete electrical isolation from
the source.
Auto Transformers
have one (1) winding that is tapped to achieve
specific output voltage. They provide no electrical isolation in a circuit.
Auto Transformers are typically smaller than their Isolation equivalent.
• Designed for 50/60 Hertz
style A
style c
–– See Accessories, pages 40-41,
for International Adapter Plugs
DImensIons-Inches
case
mounting
W
D
mW
mD
2.50
3.69
2.50
2.50
2.50
2.50
3.13
3.13
3.13
3.13
3.13
3.13
3.81
3.81
3.81
4.44
2.50
3.13
3.75
3.75
2.13
3.25
3.75
2.81
3.13
3.75
2.81
3.13
3.75
3.75
4.38
2.81
3.13
3.75
3.75
4.38
2.75
1.88
2.88
2.88
3.13
3.00
3.25
3.25
3.63
3.63
4.31
4.25
4.44
5.38
6.06
6.00
3.00
3.88
4.50
6.13
1.25
1.88
2.00
3.50
4.00
2.31
3.56
4.19
4.38
6.00
8.13
3.63
4.19
4.38
6.00
8.13
2.00
3.13
2.00
2.00
2.00
2.00
2.50
2.50
2.50
2.50
2.50
2.50
3.00
3.00
3.00
3.50
2.00
2.50
3.00
3.00
1.75
2.81
3.13
2.25
2.50
3.13
2.25
2.50
3.00
3.00
3.50
2.25
2.50
3.00
3.00
3.50
1.75
-
1.75
1.75
2.06
2.06
2.22
2.22
2.22
2.22
2.72
2.72
3.19
3.94
4.69
4.00
2.06
2.22
3.19
4.69
-
-
-
2.00
2.72
-
2.28
2.72
3.19
4.69
6.50
2.28
2.72
3.19
4.69
6.50
Weight Agency
(lbs.) certif.
2.20
1.50
3.00
2.50
3.70
3.00
4.40
4.20
5.80
5.80
7.30
7.00
10.6
14.4
17.0
20.0
3.00
5.20
10.3
17.0
0.25
1.00
1.70
3.70
6.20
1.80
4.50
7.00
9.00
16.0
31.0
4.50
7.00
9.00
16.0
31.0
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
sTAncoR
PART
sec. nUmBeR
A
P-6287
P-8620
‡
GSD-75
P-8630
GSD-100
B
P-8631
GSD-150
P-8632
GSD-250
GSD-300
C
GSD-350
P-8634
GSD-500
GSD-750
GSD-1000
GSD-1500
D
P-8638
P-8639
P-8640
P-8689
E
P-6413
‡
P-6411
‡
P-6412
‡
P-6410
F
G
P-8622†
‡
P-6406
‡
GIS-100
GIS-150
GIS-250
GIS-500
GIS-1000
H
GISD-100
GISD-150
GISD-250
GISD-500
Type
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Auto
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Isolation
Voltage
step
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Down
Up
Up
Up
Up
Straight
Straight
Straight
Straight
Straight
Straight
Straight
Straight
Straight
Straight
Down
Down
Down
Down
Down
Input
Voltage
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
230
115
115
115
115
115
115
115
115
115
115
115
115
115
115
230
230
230
230
230
output
Voltage
115
115
115
115
115
115
115
115
115
115
115
115
115
115
115
115
230
230
230
230
115
115
115
115
s115/230
115
115
115
115
115
115
115
115
115
115
115
Amps
0.35
0.43
0.65
0.74
0.87
1.10
1.30
1.74
2.20
2.60
3.00
3.50
4.30
6.50
8.70
13.0
0.54
1.30
2.17
4.35
0.005
0.13
0.30
0.43
1.30
0.43
0.87
1.30
2.17
4.35
8.70
0.87
1.30
2.17
4.35
8.70
Rms
Test
V.A. cap. Voltage style
40
50
75
85
100
125
150
200
250
300
350
400
500
750
1000
1500
125
300
500
1000
0.60
15
35
50
150
50
100
150
250
500
1000
100
150
250
500
1000
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
C
A
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
A
A
A
C
C
A
C
C
C
C
C
C
C
C
C
C
h
3.13
2.31
3.13
3.13
3.13
3.13
3.88
3.88
3.88
3.88
3.88
3.88
4.63
4.63
4.63
5.38
3.13
3.88
4.63
4.63
1.25
2.00
2.31
3.50
3.88
2.38
3.50
3.88
4.69
4.69
5.38
3.50
3.88
4.69
4.69
5.38
Straight 115/230*†
GISD-1000 Isolation
† Has electrostatic shield on separate leadwire (not grounded)
s
Secondary is two separate 115 volt windings – can be wired independently
‡
Has lead wires
*
Primary is two separate 115 volt windings
For outline drawings refer to page 39
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Au TO / i S O l AT i O N T R A N S F O R M E R S
Step-Down, Step-Up and Isolation Transformers
St yle A
d
Style C
G E N E R A L I N F O R M AT I O N
standard length of the input and output cords:
• Input Cord = 5
1
/
2
Feet minimum
• Output Cord = 8 Inches minimum
Auto/Isolation Transformers can be used in most countries by using
an input adapter plug. See page 40 for STANCOR’s high quality line of
International Adapter Plugs.
W H y & W H E R E A U T O & I S O L AT I O N
TRANSFORMERS ARE USED
Stancor’s stock Auto Transformers are connected for either step-down or
step-up applications involving line voltages of 115 or 230 Volts., 50/60 Hertz.
When isolation between the primary and secondary circuits is not necessary,
and a direct connection between them is permissible, the Auto Transformer
offers the advantages of smaller size, less weight, and lower cost.
This type of unit is generally used in applications involving American appli-
ances used abroad where our standard 115 Volt equipment must operate from
a 230 Volt source. It is also used for foreign appliances designed for 230 Volt
operation, which are to be used on our 115 Volt circuits. Our catalog items
are designed for continuous rated output on either 50 or 60 Hertz.
It is important to bear in mind that the Auto/Isolation
Transformers change only the voltage levels and do not change
the frequency from 50 to 60 hertz or vice versa. In appliances
using synchronous motors, such as clocks or phonograph record
changers and players, the speed will be different when using them
on a frequency which differs from the frequency they were origi-
nally designed. In these cases the manufacturer of the appliance
should be consulted to obtain the proper motor.
The VA rating is equivalent to a Wattage rating where a resistive load and/
or unity power factor exists. When inductive loads such as motors are used
(as in a motor driven appliance) the power factor is not unity and to be accu-
rate the output is expressed in VA, which is the product of the output voltage
and the output current (Amps).
When selecting one of these items for use with an appliance which
includes a motor, allowance should be made for the starting current of the
motor which is somewhat higher than the running current. This information
is generally available from the appliance manufacturer. Information pertaining
to the AC Wattage or current required by an appliance is generally marked
on the item by the manufacturer and should be observed. It is much better to
buy a transformer with a larger VA rating than you will actually need because
of larger motor starting currents and variations in the line voltage and/or fre-
quency in some locations, which could cause overheating.
Isolation Transformers
Used where a direct connection between primary and secondary circuits is
not desired and the circuits must be isolated. This results in a larger, heavier
and more costly item for a given power rating. However, in addition to the
isolating advantages, an electrostatic shield is generally added to minimize
capacitive coupling between primary and secondary circuits. This helps to
minimize the transfer of unwanted power line transients and interference
from other sources connected to the power line by capacitive coupling to the
secondary circuit. The standard insulation test voltage rating between wind-
ings and between each winding and the core is 1,500 Volts R.M.S. This is
normally sufficient for 115 and 230 Volt operation.
The VA rating should be selected for each specific application, with allow-
ance for any abnormal load or environmental conditions. All catalog items
have an operating temperature of 105 Degrees C. (Designed for a 65 Degrees
C. maximum temperature rise above a maximum ambient temperature for 40
Degrees C., with unrestricted free air ventilation.) V-A/Amps output ratings are
for continuous operation from the specified input voltage and frequency.
General Information
All of these items have Class “A” insulation and are rated to have a maximum
operating temperature of 105 Degrees C. These units may be used with
rectifiers but the form factor as explained elsewhere in this catalog should
be observed for various combinations of rectifier circuits and types of load
following the rectifier.
These items are made with our standard N.E.M.A. plugs and receptacles,
primarily for use in this country. However, if used overseas where different
types of plugs are necessary, an adapter plug should be used or our plug
removed and a foreign plug attached to the end of the line cord.
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