The DC shunt consists of two copper joints and an aluminum alloy profile for the resistor in the middle. By using the four-terminal connection method, the amount of current flowing through the shunt can be accurately measured. The shunt must be operated with high current flow, and the ambient temperature of the shunt will increase due to self-heating. Especially in the case of high operating temperature and poor geography of the heat pipe radiator, the ambient temperature of the shunt will increase further.
According to the Electrical Equipment and Electronics Engineers Promotion Association standard, under all normal operating specifications, the highly recommended operating current of the DC shunt should not exceed 2/3 of the rated current.
But we don't know that in practical applications, it is often necessary to accurately measure a wide range of current, that is to say, everyone requires the DC shunt to work normally at 10%-100% of the rated current, and sometimes there may even be short-term load.
Regardless of operating specifications, it is important to control the ambient temperature of the shunt. Its working responsibility is the best at 30℃~70℃, and its ambient temperature cannot exceed 145℃ under all circumstances, otherwise the resistance value of the aluminum alloy profile of the resistor will cause a reversible change. In particular, the ambient temperature of the shunt should be accurately measured from the selection point of the resistor aluminum alloy profile.
If you use DC separation, due to the two sides of DC separation, we will have a difficulty, that is, how to manage and decide its direction when DC is separated?
Everyone knows that a DC shunt is actually a very small resistor. When there is an AC circuit flowing, it causes an amount of current to be displayed by the DC ammeter. To accurately measure large AC circuits, use DC current shunts whenever possible. A shunt is a precise resistor that can handle large amounts of current.
When the amount of current crosses the shunt, a working standard voltage of millivolts will appear on both sides. Therefore, we use a millivolt ammeter to accurately measure this working standard voltage, and convert this working standard voltage into a current, so as to carry out accurate measurement of large current. Connect the two current flow terminal blocks of the selected shunt to the power transformer and the load, respectively. The potential difference terminal block is connected to the ammeter. Attention should be paid to the optical rotation of the interconnected ammeter terminal blocks. The range of the ammeter will be extended to the amount of current calibrated on the shunt. So you can see that the two sides of the DC shunt can be connected to the power transformer and the load respectively, so the DC shunt has no direction.
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