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磁势平衡电流互感器 (Core Balance Current Transformer)--CBCT

  • Units in Stock: 100

Core Balance Current Transformer CBCT


磁势平衡电流互感器 (Core Balance Current Transformer) CBCT
1. 用于:漏电电流测量
2. 初级电流(不平衡电流) : 30mA 至 300mA
3.饱和电流: > 3 A
4. 主绕组: 1转
5. 次级:   2个相同绕组
 (a): 预计电压负担抵抗是2 V @初级电流300mA的。如果2 V输出电压是不可能的,请建议最大的可负荷二次电压是多少。
 (b): 同(a)规格
6. 系统电压:600V
7. 系统频率: 50/60HZ
8. 绝缘电压: 4kv
9 精度等级:1
10. 工作温度:250C to +650C
11. CBCT和继电器的距离:50米
12. 建议的互感器的净尺寸:
最小的内径:42 mm (+/- 1 mm)
       最大的外径:76 mm (+/- 1 mm)
       最大的高度: 20 mm (+/- 1 mm)
13. 期望的带封装的内径: = 35 mm
1)      Application: Earth Leakage Current Measurement
2)      Primary Current (Unbalance current): 30 mA to 300 mA
3)      Saturation Current: > 3 A
4)      Primary Winding: 1 Turn
5)      Secondary:
Two identical windings.
       A) Secondary 1:
      Expected voltage across burden resistance is 2 V @ primary current of 300mA. If 2 V output voltage is not possible, please suggest the maximum secondary voltage that can be achieved across secondary burden.
       B) Secondary 2:
            As per Secondary 1.
6)      System Voltage: 600 V
7)      System frequency: 50 / 60 Hz
8)      Insulation Voltage : 4 kV
9)      Accuracy Class: 1
10)   Operating Temperature: -250C to +650C
11)    Distance between CBCT and Relay: up to 50 m.
Effect of wire resistance on secondary voltage should be negligible. Measured resistance of 4 core shielded cable for 50 m is approximately 10 ohm.
12)    Preferred Mechanical Dimensions of bare CT:
Min. ID: 42 mm  (+/- 1 mm)
       Max OD: 76 mm (+/- 1 mm)
       Max HT: 20 mm (+/- 1 mm)
13) Expected ID with Casing = 35 mm.                      
       Note: Refer attached drawing for mechanical dimensions of casing of CBCT which is presently in field.


Core Balance Current Transformer

Core Balance Transformer

Core-Balance Transformer

CBCT wave

1. Diffrential current 30 mA to 300 mA is flowing througngh P1 and P2
2. Voltage 200 mV to 2 V is developed across Burden resistor i.e. S1 and S2
3. T1 and T2 are used to TEST Relay i.e. simulate trip and verity CT connection
4. Resisistors RS and RS1 is selected to develope 2 V acrooss S1 and S2
5. Switch SW1 and SW2 are Digital C-MOS switches
6. Relay Verifies CT Conncetion 4 to 5 times per second



testing report of CBCT


1. Frankly speaking, we don't have any sample in hand at this moment.

But I can give you the specification of one of the CBCT I've found on the website. It is similar to our requirement at some extent. So, pls go thru the attached .doc file.

2. Secondly, pls read the below paragraph carefully for better understanding of this CT.

        "CT will have two Secondary Windings. Let's assume the Primary Winding as P1-P2 (wire passed through CT), Main Winding as S1-S2 and Test Winding as T1-T2. Burden will be connected across S1-S2. A +/-5V square wave source (2kHz) with series resistance will be connected across T1-T2.
       So, when there is 300 mA current through P1-P2, 2 V output will be generated across S1-S2 and at that time, by applying a voltage across T1-T2, our relay will verify CT connection. When there is no current through P1-P2 and voltage is applied to T1-T2 (say 2 V after series resistance), same voltage (i.e. 2 V) should be developed across S1-S2. For better understanding of this, pls refer the attached drawing."

3. With reference to the specifications we are sending to you, we would want to convert to the 2V output at a primary of 300 mA within the Control Relay itself to avoid any kind of measurement errors due to different lengths of wires from secondary of the CT to the Control Relay. So, pls specify the exact burden requirement to be put within our Control Relay. We are expecting the samples soon from your side with the other specifications intact.

4. Considering all the above points, pls send us the specifications once you developed the CT before sending the samples. We will require 20 samples for testing purpose. Once these samples are approved, we'll require 300 pcs of these CTs immediately. Our annual quantity will be 4000. So, pls send us the quotation accordingly.

5. Pls fill up the data required in the attached spreadsheet for CT's Test Report.

6. Even if mould is not there at this moment, you can proceed without it and design for taped wound construction.