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How does Manganese-Copper Shunt Resistor Make Proper Connection in Intelligent Meter?
Date:2019-04-04
Manganese-copper shunt resistor adopts high-temperature brazing and fusion welding technology, ensures strong connection, stable resistance value and good performance. Microhm
continues to develop and research new structures. Mn-Cu shunt resistor has many specifications, such as 120 μ Ω, 175 μ Ω, 200 μ Ω, 250 μ Ω, 300 μ Ω, 350 μ Ω, 400 μ Ω, 500 μ Ω, 600 μ Ω, 800 μ Ω, 1000 μ Ω, resistance tolerance is ±5%, pore distance and aperture can be customized. Mn-Cu divider is suitable for all kinds of electric energy meters with different currents.
 
 
The hardware of electronic intelligent meter mainly includes metering module, man-machine interface and power supply. If these hardware components are changed artificially, they will result in abnormal metrology of smart meters. In some cases, additional electromagnetic pulse interference may cause temporary or permanent fault of the smart meter, so that the smart meter does not count or undercount the electricity, leading to the theft of electricity.
 
On-the-spot inspection, MnCu shunt can not be ignored, the mn-Cu sheet as a shunt resistance Rs, when the large current i (t) flow will produce a direct ratio of the weak voltage Ui (t), the mathematical expression is: Ui (t) = i (t) Rs. The small signal Ui (t) is fed into the multiplier to measure the current i (t) flowing through the smart meter. When the MnCu resistor with thickness of 2mm and sampling resistance of 200μΩ, current following through is 5A, the sampling signal between 1 and 2 is Ui=RI= 200 μ Ω × 5A=1mV.


 
Mn-Cu splitters measure the current schematic diagram and change the connection of the sampling signals. If the resistance R 'between 2 and 3 is less than the sampling resistance, for instance 100 μ Ω, then when the current is 5A, the resistance between 2 and 3 is only 0.5mV,
which is obviously smaller than the normal sampling signal Ui (1mV), that is, the input signal of the measuring chip is only 50% of the normal value, so the input current measured by the measuring chip is Is=0.5/1 × 5 × 2.5A.
 
When the smart meter input current is 5A, the input current measured by the metering chip is only 2.5 A, resulting in a 50% error in the metering. Therefore, the change of the electric quantity is E '= (R'/ R). E0 refers to the amount of power to be accumulated in the smart meter. E ' means cumulative amount of electricity displayed by the Intelligent meter after change.
The manganese-copper shunt is used more and more in the intelligent electric meter product, and the high-end precision copper-manganese shunt is also continuously improving the production process. There is a great improvement in precision. Smart meter will be more accurate and benefit citizen's life.