## Tuesday, September 26, 2023

Two Wattmeter Method of Power Measurement

Two Wattmeter Method can be employed to measure the power in a 3 phase, three-wire star or delta connected to the balanced or unbalanced load.

In two wattmeter method, the current coils of the wattmeter are connected with any two lines, say R and Y and the potential coil of each wattmeter is joined on the same line, the third line i.e. B as shown below in figure (A):

The total instantaneous power absorbed by the three loads Z1, Z2 and Z3, is equal to the sum of the powers measured by the two wattmeters, W1 and W2.

Contents:

Measurement of Power by Two Wattmeter Method in Star Connection

Measurement of Power by Two Wattmeter Method in Delta Connection

Measurement of Power by Two Wattmeter Method in Star Connection

Considering the above figure (A) in which Two Wattmeter W1 and W2 are connected, the instantaneous current through the current coil of Wattmeter, W1 is given by the equation shown below:

A voltmeter is an instrument used for measuring the electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; Digital voltmeters give a numerical display of voltage by use of an analog-to-digital converter.

Three Phase Voltmeter Connection Switch. A voltmeter is placed in parallel with the voltage source to receive full voltage and must have a large resistance to limit its effect on the circuit. An ammeter is placed in series to get the full current flowing through a branch and must have a small resistance to limit its effect on the circuit.

Two Wattmeter Method of Power Measurement

Two Wattmeter Method can be employed to measure the power in a 3 phase, three-wire star or delta connected to the balanced or unbalanced load.

In two wattmeter method, the current coils of the wattmeter are connected with any two lines, say R and Y and the potential coil of each wattmeter is joined on the same line, the third line i.e. B as shown below in figure (A):

The total instantaneous power absorbed by the three loads Z1, Z2 and Z3, is equal to the sum of the powers measured by the two wattmeters, W1 and W2.

Contents:

Measurement of Power by Two Wattmeter Method in Star Connection

Measurement of Power by Two Wattmeter Method in Delta Connection

Measurement of Power by Two Wattmeter Method in Star Connection

Considering the above figure (A) in which Two Wattmeter W1 and W2 are connected, the instantaneous current through the current coil of Wattmeter, W1 is given by the equation shown below:

A voltmeter is an instrument used for measuring the electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; Digital voltmeters give a numerical display of voltage by use of an analog-to-digital converter.

Three Phase Voltmeter Connection Switch. A voltmeter is placed in parallel with the voltage source to receive full voltage and must have a large resistance to limit its effect on the circuit. An ammeter is placed in series to get the full current flowing through a branch and must have a small resistance to limit its effect on the circuit.