460-480 Tyco Electronics, 460-480 Datasheet - Page 132

• Manufacturer Part Number: 460-480
• Description: Voltage Transformer
• Manufacturer: Tyco Electronics
• Series: 460r

Specifications of 460-480

• Turns Ratio: 4
• Transformer Mounting: Chassis
• Voltage Ratio: 480
• Primary Voltages: 480V
• Power Rating: 150VA
• Output Voltage: 120V
• Mounting Type: Foot Mounted
• Transformer Type: Voltage
• Lead Free Status / RoHS Status: na

134
Voltage Transformers Burden Data
Voltage transformers have the same accuracy classes as indicated in Table 1 (i.e. 0.3, 0.6 and
1.2). These accuracy classes must be given at a stated burden in order to be meaningful.
The following table gives the standard burden data:
In summary if you have a “0.6Y" accuracy and burden statement this means: (0.6) maximum
ratio error of +0.6% at a burden of 75VA with a power factor of 0.85.
Current Transformers Ratio Modification
Relatively large changes in ratio may be achieved through the use of primary turns,
for example:
A primary turn is the number of times the primary conductor passes through the CT’s
window. The main advantage of this ratio modification is you maintain the accuracy and
burden capabilities of the higher ratio. The higher the primary rating the better the accuracy
and burden rating.
You can make smaller ratio modification adjustments by using additive or subtractive
secondary turns. For example if you have a CT with a ratio of 100:5A. By adding one
additive secondary turn the ratio modification is 105:5A, by adding on subtractive secondary
turn the ratio modification is 95:5A. Subtractive secondary turns are achieved by placing the
"X1" lead through the window from the H1 side and out the H2 side. Additive secondary
turns are achieved by placing the "X1" lead through the window from the H2 and out the H1
side. So, when there is only one primary turn each secondary turn modifies the primary
rating by 5 amperes. If there is more than one primary turn each secondary turn value is
changed (i.e. 5A divided by 2 primary turns = 2.5A). The following table illustrates the
effects of different combinations of primary and secondary turns:
CT Ratio 100:5A
Burden
Primary Turns
W
X
M
Y
Z
ZZ
1
1
1
2
2
2
3
3
3
100:5A
200:5A
300:5A
100:5A
200:5A
300:5A
100:5A
200:5A
300:5A
CT Ratio
Volt Amperes
12.5
25
35
75
200
400
2
2
2
3
3
3
4
4
4
Number of Primary Turns
Secondary Turns
–0–
–0–
–0–
1+
1–
1+
2–
1+
1–
Power Factor
0.10
0.70
0.20
0.85
0.85
0.85
Modified Ratio
50:5A
100:5A
150:5A
33.3:5A
66.6:5A
100:5A
25:5A
50:5A
75:5A
Ratio Adjustment
100:5A
105:5A
95:5A
50:5A
52.5:5A
45.0:5A
33.3:5A
34.97:5A
31.63:5A
P.F. Angle
84.3°
45.6°
78.5°
31.8°
31.8°
31.8°