Correct wiring method when measuring single-phase AC current with AC ammeter

The correct wiring method when using an AC ammeter to measure single-phase AC current is as shown in the figure. Figure (a) shows the direct connection method of an AC ammeter, which is suitable when the measurement range is within the range tolerance; Figure (b) shows the connection method of an AC ammeter with current, which is suitable when the measurement limit needs to be expanded or must be reduced. The condition of current passing through the instrument. But please note: the selected variable ratio must be consistent with the ammeter.

Figure common wiring circuits for AC ammeters

(a) Direct connection method; (b) Connection method with current transformer

Figure (a) is measured by connecting the ammeter in series to the load circuit to be measured; Figure (b) is measured by the ammeter after being detected by the current transformer.

When using AC transformers, the secondary side of the AC transformer is not allowed to be open circuit, otherwise high voltage will be generated and cause great harm to people or equipment.