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Selection of low-voltage residual current transformers

Selection of low-voltage residual current transformers

Low voltage residual current transformers are dedicated to collecting residual current and are used in conjunction with electrical measurement and control devices and motor protection devices. This product can have two outputs for the secondary, one can output 0-20mA or 0-2mA, and the other can output 0-1V. You can only choose one of the two.

Selection instructions:

Select the corresponding specification product based on parameters such as primary current and bus section. Once the wire passes through the transformer window hole. Open the flip cover and perform secondary wiring through the crimping piece. After the secondary wiring is led out, reset the flip cover. Electricity metering can be directly achieved by sealing the small holes on the flip cover with a lead seal to prevent electricity theft.

The working current should not exceed 1.1 times the rated value for a long time, and short-term use is allowed at 1.2 times the rated value for no more than 1 hour;

According to the magnitude of the measured current, select the rated current ratio, generally selecting a rated current that is about 2/3 larger than the measured current;

The polarity of the product is represented as: primary wiring symbols P1 and P2, and corresponding secondary wiring symbols S1 and S2; S1 represents the homonymous end of P1, and S2 represents the homonymous end of P2;

The measuring instrument is connected to terminals S1 and S2, and the total load of the connected circuit should not exceed the rated load of the transformer. When the installation position of the instrument is far from the current transformer or the circuit load is large, the specification with a secondary current of 1A should be preferred;

Pay attention to selecting transformers with matching window sizes based on the specifications and number of busbars.

Used in conjunction with electrical fire monitoring devices or leakage current relays, it can detect 0-1A leakage current (small leakage current of 6mA) and output 0-1V or 0-2mA.

The motor protection unit is used in conjunction to measure ground faults and can overload up to 10 times.


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