GDZX ZXHQ-A+ CT, Руководство пользователя, Страница: 22 / 23

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printer showing the smooth surface, take out a small amount of paper and press down
the panel. If the printing condition is normal, but there are no words or curve on the
paper, the paper is installed inversely.
3. Warranty period: 1 year.
Error Curve Explanation
According to the data of 5% and 10% error curves between the current multiple
（
M
）
and
permissible secondary load
（
ZII
）
worked out based on excitation current and voltage on the
secondary side of the transformer, we can decide whether the protection winding of the
transformer is qualified;
The actual load measured based on the theory current multiple is greater than the theory
load marked on the transformer nameplate, which indicates the transformer is qualified if it
is in conformity with the data in the Figure 40,:
The actual current multiple measured based on the theory load is greater than the theory
current multiple marked on the transformer nameplate, which also indicates the transformer
is qualified if it is in conformity with the data in the Figure 40:
The secondary load of the protection type current transformer shall meet the requirement of
5% error curve. Once the actual secondary load of the current transformer is less than the
load permissible by the 5% error curve, the measurement error of the qualified current
transformer is within 5% based on the rating current multiple. If the secondary load is great,
the core of the current transformer is easy to get saturated, and the permissible current
multiple will be small. Therefore, 5% error curve, namely n/ZL curve is the curve shown in
Figure 18. As for protection type CT (5P10 20VA)shown in Figure 40, 5 is class of
accuracy(error limit is 5%), P is transformer type(protection class), 10 is accurate limit value
factor(10 times of rating current), 20VA is rating secondary load(capacity).
When the
current multiple is 10.27(approaching 10 ), the permissible secondary load is 27.19Ω,
greater than the rating load 20VA(20VA/1=20Ω) of this CT, which indicates the transformer
is qualified. In addition, when the secondary load is 19.58Ω(approaching 20Ω), the
permissible current multiple is 12.85, greater than the rating current multiple 10 of this CT,
which indicates the transformer is qualified. In fact, either of the above factors can indicate
the transformer is qualified.