Lead Wire Zero Phase Current Transformer ZCT Current Transformer Coil
Customized Zero Phase Current Transformer ZCT current transformer Coil Are Available Upon Request
General introduction and definition of Zero Phase Current Transformer
1. The basic function of current transformers
The current transformers can convert primary currents with larger values to secondary currents with lower values through a certain transformation ratio, which are used for protection and measurement purposes. For example, a current transformer with a transformation ratio of 400/5 can convert the actual 400A current to 5A current.
2. Working principle of zero sequence current transformer
The basic principle of zero-sequence current protection is based on Kirchhoff’s current law: the algebraic sum of the complex current flowing into any node in the circuit is equal to zero. When the line and electrical equipment are normal, the vector sum of each phase current is equal to zero. Therefore, the secondary winding of the zero sequence current transformer has no signal output, and the actuator does not operate. When the ground fault occurs, the vector sum of each phase current is not zero. The fault current causes magnetic flux in the ring core of the zero-sequence current transformer. The induced voltage on the secondary side of the zero-sequence current transformer causes the actuator to move and drive Trip device to switch the power supply network to achieve the purpose of ground fault protection.
3. The function of ZCT Current Transformer Coil
When an electric shock or leakage fault occurs in the circuit, the protection acts and the power supply is cut off.
4. Conditions of use for zero phase current transformers
A current transformer can be installed on each of the three-phase lines, or three-phase conductors can be passed through a zero-sequence current transformer together, or a zero-sequence current transformer can be installed on the neutral line N to use it to detect three phases. Vector sum of current.
For the specific application of zero-sequence current protection, a current transformer (CT) can be installed on each of the three-phase lines, or three-phase conductors can be passed through a zero-sequence CT together, or a zero-sequence CT can be installed on the neutral line N. These CTs are used to detect the vector sum of three-phase current, that is, the zero-sequence current Io, IA+IB+IC=IO, when the three-phase load connected to the line is fully balanced (no ground fault, and the leakage current of the line and electrical equipment is not considered ), IO=0; when the three-phase load connected to the line is unbalanced, then IO=IN, and the zero-sequence current at this time is the unbalanced current IN; when a ground fault occurs in a phase, a single-phase ground must be generated The fault current Id, the zero sequence current detected at this time IO=IN+Id, is the vector sum of the three-phase unbalanced current and the single-phase ground current.

Zero Phase Current Transformer Applications
– Residual current circuit breaker (RCCB)
– Earth leakage circuit breaker (ELCB)
– Ground fault circuit interrupter (GFCI)
– Appliance leakage circuit breaker interrupter (ALCI)
– ZCT for energy storage system (ZCT’s)
ZCT Current Transformer Coil Features
– Minimum output voltage tolerance
– Close to zero load shift
– Minimum noise output at 360 degree hair-pin test.
– Excellent thermal properties in minimal variation
-Customized products are available
Zero Phase Current Transformer Main Materials and Electrical Diaphram
Zero Phase Sequence ZCT Current Sensor Transformers Main Materials | |
Core | 80% Ni amorphous or nanocrystaline core |
Core case | PBT 1320 (UL file NO E221630) |
Windings | 2-UEN φ0.08mm (UL file NO E164502) |
Shield | metal shield |
Epoxy Resin | Epoxy resin 9001A/B (UL file No E105888) |
Outer Case | PBT 1320 (UL file NO E221630) |
Lead wire | PVC insulated wire 1007 #26AWG (UL file NO E186019) |

ZCT Current Transformer Coil Electrical Property & Dimension

Model No | Rated current | Output voltage (V0/mV) | Test Condition | Over leakage characteristics | Temperature Characteristics
(35ºC-80ºC) |
Dimensions (mm) | |||
A | B | C | D | ||||||
KXRKCT506 | 30 | 4-5.1 |
lin=10mA RL=510 |
-10%~0% |
10%Max |
5.9 | 16 | 16 | 6.5 |
KXRKCT507 |
30 |
5.1-6 |
lin=8mA RL=750 |
-10%~0% |
10%Max |
5.8 | 15.2 | 15.2 | 6.1 |
KXRKCT509 |
50 |
17-21 |
lin=22.5mA RL=1k |
-10%~0% |
10%Max |
9.2 | 21 | 21 | 7.3 |
KXRKCT510 |
30 |
12-15 |
lin=22.5mA RL=1k |
-10%~0% |
10%Max |
9.8 | 6.5 | 6.5 | 20.6 |
KXRKCT509B |
30 |
12.5-15.5 |
lin=8mA RL=4.7k |
-10%~0% |
10%Max |
9.3 | 21.3 | 21.3 | 7.2 |
KXRKCT512 |
50 |
17-21 |
lin=22.5mA RL=1k |
-10%~0% |
10%Max |
12.3 | 26 | 26 | 10 |
KXRKCT515 |
30 |
7.5-8.5 |
lin=25mA RL=1k |
-10%~0% |
10%Max |
15.4 | 29.8 | 29.8 | 10 |
KXRKCT507 |
60 |
10.2-12.5 |
lin=20mA RL=680 |
-10%~0% |
10%Max |
7.2 | 19.4 | 19.4 | 7.7 |
KXRKCT510B |
50 |
8-11.2 |
lin=11.25mA RL=1k |
-10%~0% |
10%Max |
7 | 17.2 | 17.2 | 7 |
KXRKCT507 |
50 |
8-11.2 |
lin=11.25mA RL=1k |
-10%~0% |
10%Max |
6.8 | 16.9 | 16.9 | 7.9 |
KXRKCT510C |
50 |
8-11.2 |
lin=11.25mA RL=1k |
-10%~0% |
10%Max |
10.6 | 25.4 | 25.4 | 8 |
KXRKCT509C |
60 |
10.2-12.5 |
lin=20mA RL=680 |
-10%~0% |
10%Ma |
11 | 23.5 | 23.5 | 8 |
KXRKCT509D |
60 |
≥300 |
lin=25mA RL=1k |
-10%~0% |
10%Max |
9.4 | 23.8 | 23.8 | 12.7 |
KXRKCT507B |
60 |
10.2–12.5 |
lin=25mA RL=680 |
-10%~0% |
10%Max |
7.5 | 18.9 | 18.9 | 7.6 |
KXRKCT510D |
60 |
≥300 |
lin=25mA RL=47k |
-10%~0% |
10%Max |
10.1 | 24 | 24 | 11.5 |
KXRKCT511 |
60 |
≥300 |
lin=25mA RL=47k |
-10%~0% |
10%Max |
10.9 | 25.5 | 25.5 | 9 |
KXRKCT515B |
100 |
17-21 |
lin=22.5mA RL=1k |
-10%~0% |
10%Max |
15 | 29.2 | 29.2 | 10 |
KXRKCT524 |
225 |
125-150 |
lin=500mA,RL=150 |
-10%~0% |
10%Max |
24 | 42 | 42 | 12 |
KXRKCT543 |
400 |
125-150 |
lin=500mA,RL=150 |
-10%~0% |
10%Max |
43 | 90*74 | 90*74 | 16 |
NOTE:
Above are just some of our models. More to come!
Customized products are available upon request
Other Related Current Transformers, Please click on below pictures
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