How range of A.C. ammeter & A.C. voltmeter is extended? Draw suitable diagram.
1 Answer
Extension of A.C. Ammeter Range: The range of a.c. ammeter can be extended by using CT, the arrangement is shown in figure. The CT is current transformer having less number of primary turns carrying high magnitude of line current and more number of secondary turns hence reducing the secondary current as per its CT ratio. The low range ammeter can be connected in secondary circuit for measurement of reduced line current, which indirectly measure high magnitude of line current. In this way range of a.c. ammeter can be extended.
Extension of A.C. Voltmeter Range: The range of a.c. voltmeter can be extended by using PT, the arrangement is shown in figure. The PT is potential transformer having more number of primary turns connected to the high voltage source and less number of secondary turns hence reducing the secondary voltage as per its PT ratio. The low range voltmeter can be connected to secondary for measurement of reduced source voltage, which indirectly measure high magnitude of source voltage. In this way range of a.c. voltmeter can be extended.