Anhui, China
Business Type:
Number of Employees:
Year of Establishment:
Management System Certification:
OHSAS18001:2007, ISO9001:2015 Certificate, ISO14001:2015 Certificate
Average Lead Time:
Peak season lead time: within 15 workdays
Off season lead time: within 15 workdays
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Current, Over Voltage, Protector manufacturer / supplier in China, offering Current Transformer Secondary Overvoltage Protector, Km-Ftb Large Capacity Explosion-Proof Overvoltage Protector, Km-Gdy Over Voltage Suppression Cabinet and so on.

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Current Transformer Secondary Overvoltage Protector

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Min. Order / Reference FOB Price
50 Pieces US $150-985/ Piece
Port: Shanghai, China
Production Capacity: 1000 Pieces/Month
Payment Terms: L/C, T/T, D/P, Western Union, Paypal, Money Gram
Application: Electronic
Type: Current Transformer
Phase: Three
Operation Condition: Indoor
Usage: Protection
Winding Form: Small Fixed Type

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Basic Info

Model NO.
Insulating Medium
Common Insulating Materials
Active Type
Magnetic Circuit Structure
Combined Type
Voltage Transformation Principle
Capacitive Type
Transport Package
Chinese, Hefei
KM-CTB current transformer secondary overvoltage protector
When current transformer (CT) in the operation, the secondary winding is open, or the primary winding flows abnormal current (such as lightning current, resonant over current, capacitor charging current, inductor starting current, etc.), it will be generated several thousands overvoltage or even tens of thousands of overvoltage. Which not only causes damage to the insulation of the secondary system, but also causes the transformer to be over-excited and burned, and even endangers the life safety of the operating personnel.
According to the actual needs of the power system, based on the first generation of protectors, our company has developed a protector (KM-CTB) with an action contact output, automatic light display, automatic lock differential protection, manual and automatic reset function after operation, and multiple combinations of different functions. With new automatic control technology and high reliability components, the product has a long service life and more than 100,000 times reliably operate. It has high action speed, strong overload capability and small static leakage current, which can meet the needs of various CT protection.
Current Transformer Secondary Overvoltage Protector
Current Transformer Secondary Overvoltage Protector

KM-CTB is mainly used for abnormal overvoltage protection on the secondary side of various CT. The protector is fixed at both ends of the CT secondary winding. The leakage current is extremely small during normal operation and is in a high-resistance state. When the CT secondary circuit is open or an abnormal current occurs in the primary winding, the voltage generated by the secondary winding is much higher than that, at this time the protector quickly acts and short circuit, the faulty part is displayed on the panel, and the passive contact signal is output. After the fault is removed, pressing the manual reset button, and the circuit will return to normal operation after returning to the original state.

Basic functions
The input impedance  higher than 100MΩ does not affect any measurement and protection performance after access;
The secondary side protection voltage can be set  to meet different occasions;
After the protection, there is a fault point position display to facilitate troubleshooting
After protection, there is contact signal output, which is convenient for system connection;
After the protection, there is an alarm sound prompt, which promptly reminding to eliminate the fault;
After the protection, there are  manual button reset and automatic reset after the fault disappears, which is convenient for the user to select;
The area is saved and the track installation design is convenient for installation and use;

Model Description
Current Transformer Secondary Overvoltage Protector

Technical Parameters
Normal Leakage current IL20V1uA
Input   Resistance>1000MΩ
ON  voltage450V±10%(Factory setting, user can set it)
ON  time50msTs250ms
Alarm output contact capacityAC220V/5A;DC110V/5A
Protection relay contact capacityAC220/5A
Use CT specificationsThe secondary side peak is higher than 150V
Protection current5A
Working environmentTemperature: -20ºC~+70ºC  Humidity: 95%RH
Reset modeManual button reset; automatic reset (optional)
Seismic performance10-50-10HZ 2g 3min
Reliable securityMeets IEC834-1 requirements
Working power supplyAC220V, 50HZ
Power consumption5W
Installation methodTrack installation 

Product selection catalog
        ModelNumber of windings                          External size
KM-CTB-11 windingLength: 62mm Width: 72mm Height: 112mm
KM-CTB-22 windingsLength: 62mm Width: 72mm Height: 112mm
KM-CTB-33 windingsLength: 62mm Width: 72mm Height: 112mm
KM-CTB-44 windingsLength: 82mm Width: 72mm Height: 112mm
KM-CTB-5 5 windingsLength: 82mm Width: 72mm Height: 112mm
KM-CTB-66 windingsLength: 82mm Width: 72mm Height: 112mm
KM-CTB-7~97~9 windingsLength: 112mm Width: 72mm Height: 112mm
KM-CTB-10~1810~18 windingsLength: 132mm Width: 72mm Height: 112mm
For protection of 6 windings or more, the protector is a non-standard product. The company can provide a single current transformer secondary overvoltage protector that protects 18 windings.

Installation, on-site inspection and maintenance

1. installation
The protection device installation point should be as close as possible to the protected CT for easy inspection. When the lead wire is long, the armored cable should be used as much as possible to prevent disconnection.
2. On-site inspection
The protector should be tested before use. When testing the A (or B or C) and N ends with  multimeter resistance , the insulation resistance value should be greater than tens of mega ohm.
 When the action value is tested, adjust the voltage regulator to 0V position firstly, turn on the protector and voltage regulator with AC220V power supply, the protector work indicator lights up, then increase the regulator output voltage slowly to the protector action voltage value, this voltage is instantaneously applied to the A (or B or C) and N ends of the protector. At this time, the protector should be operated, and the corresponding action indicator light is on. At the same time, the protector output contact is measured with  multimeter, the open contact is closed, and the closed contact is opened. Finally press the reset button, the action indicator should be off after the protector is reset.
When testing circuit, current limiting resistor should be added, and  adjust the output current within 10 mA.
3. Any type of KM-CTB is maintenance-free and can be inspected once a month and detected once every three years.

Service and quality commitment
If the user complies with the storage and use requirements, the product damaged or not working properly due to quality reasons, 12 months from the date of installation or use, or 18 months from the date of shipment. The company will repair or replace product for free.

Current Transformer Secondary Overvoltage Protector
Current Transformer Secondary Overvoltage Protector

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