What Are The Basic Circuits Of Ac Clamp Ammeter For Power Fittings?

How many basic circuits are there for a Single Pole Distribution Blocks AC clamp ammeter?
Several basic circuits for common AC clamp ammeters are shown in Figure 5-2.
The shunt resistors R1~R6 of the secondary current in Figure 5-2(a) change with the conversion of the range. For example, for a 60A range, the shunt resistors are R3, R4, Rs and Re; the shunt resistors for a 15A range are all Rr~R6; and the shunt resistor for a 1000A range is only R6, and the rest are short-circuited by the conversion switch. When adjusting the error of a certain range in this circuit, it is necessary to consider how many shunt resistors are used for the range, which shunt resistors are shared, and which resistor has the least effect on the others.
In Figure 5-2(b), the secondary measured current of the transformer is shunted and rectified before entering the measuring mechanism to indicate the reading. The characteristic is that the error of each range is the same, R6 is a shared resistor, and adjusting it can eliminate the error of the instrument. If the errors of each range are not equal, the dedicated shunt resistors of each range can be adjusted separately, and the ranges will not affect each other.
The measurement circuit in Figure 5-2(c) is basically the same as Figure 5-2(a), except that several additional resistors are added to the measurement circuit for measuring AC voltage. When measuring AC voltage, no transformer is used, and additional wiring is used for measurement. The error adjustment of the voltage range can eliminate the error by simply increasing or decreasing the additional resistor.