Operating Instructions Z-D-15/35/55E-..
Installation instructions
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L-BAL-E321-GB 2021/11 Index 002
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5.3.6
Selection of CT (current transformers)
Selection of current transformers depends on the load current of the application. Applicable are current
transformers in the range of 30:5 to 250:5. The transfer ratio must be adjusted in the correlated
parameter of the software. For optimal performance, the nominal current of the current transformer must
not be much higher than the load current of the application (e.g. load current 95A => current transformer
100A)
Following CT´s are provided for corresponding nominal current
Nominal current of CT (current
transformer)
1
in A
Filter
Nominal current of filter
2
in A
Order code
3
CT
30
Z-D-15E-030
15
349110
40
Z-D-15E-040
15
349111
50
Z-D-15E-050
15
349112
60
Z-D-15E-060
15
349114
60
Z-D-35E-060
35
349115
80
Z-D-35E-080
35
349116
100
Z-D-35E-100
35
349117
150
Z-D-35E-150
35
349118
150
Z-D-55E-150
55
349119
200
Z-D-55E-200
55
349120
250
Z-D-55E-250
55
349121
1
Current transformers should be selected based on the maximum load current to be filtered and the
THDi target to be achieved
2
Relates to the maximum possible compensation current
3
Each part number consists of a filter and 2 current transformers
5.3.7
Wiring when using current transformers with high ratio
For part numbers 349110, 349111 and 349112 the conductor of the load current must be passed through
the converter two times (loop once) to achieve the correct current transformer rating. It is essential (as
with simple implementation) that the direction of energy flow in the conductor and the direction of the
arrow on the converter match. A 100A bushing current transformer is used as an example for part
number 349112, here the conductor must be passed through twice instead of once. See capture 5.3.
Such an adaptation is not possible with converters without a feed through.
If you have any questions, please contact our technical support for control systems - ventilation
technology.
