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Experiment No.: Aim: - To Measure Three Phase Power and Power Factor in A Balanced Three Phase Circuit Using

This document describes an experiment to measure three-phase power and power factor in a balanced and unbalanced three-phase circuit using two single-phase wattmeters. The two wattmeter method is commonly used and allows measurement of total power by summing the two wattmeter readings, even for unbalanced loads. The experiment involves setting up a three-phase circuit with loads, a wattmeter on two lines and a voltmeter, then recording voltage, current and wattmeter readings under balanced and unbalanced load conditions to calculate total power consumed.

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641 views5 pages

Experiment No.: Aim: - To Measure Three Phase Power and Power Factor in A Balanced Three Phase Circuit Using

This document describes an experiment to measure three-phase power and power factor in a balanced and unbalanced three-phase circuit using two single-phase wattmeters. The two wattmeter method is commonly used and allows measurement of total power by summing the two wattmeter readings, even for unbalanced loads. The experiment involves setting up a three-phase circuit with loads, a wattmeter on two lines and a voltmeter, then recording voltage, current and wattmeter readings under balanced and unbalanced load conditions to calculate total power consumed.

Uploaded by

gejal akshmi
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Experiment No.

Aim: - To measure three phase power and power factor in a balanced three phase circuit using
two single-phase wattmeter. Calculate the three phase power for unbalance load condition.

Apparatus: -

1. Three Phase Load.


2. A.C Wattmeter - 2 nos.
3. A.C Voltmeter.
4. A.C ammeters.
5. Three Phase supply
6. Connecting Wires.

Theory: - Single phase power can be measured using single wattmeter, But for measurement of
3 phase power can be done using following methods:

1. One wattmeter method.


2. Two wattmeter method.
3. Three wattmeter method.

Figure 1 Connection diagram for two-wattmeter method of measuring three phase power

Basics of Electrical Engineering EED, SSEC, Bhavnagar Page No.


Two wattmeter method

This method is commonly used for the power measurement in the 3 phase circuits. Here as name
suggests, only two wattmeters are used. The current coils of the two wattmeters are connected in
series on any two lines. The corresponding pressure coils are connected between these lines and
the third line on which no wattmeter is connected.

The two wattmeter method is used for the power measurement in the 3-phase systems,
irrespective of whether the load is balanced or unbalanced, star or delta connected.

For resistive load cos = 1.

The above equation shows that the sum of the two wattmeter readings gives the total power
consumed in the three-phase balanced system. We can also calculate the load power factor angle
from the measurement of W1 and W2.

For Unbalance Load Condition:

Basics of Electrical Engineering EED, SSEC, Bhavnagar Page No.


× 100

Procedure:-

1. Make the connections as per the circuit diagram.


2. Switch on A.C supply.
3. For balanced load condition measured the values of wattmeters, ammeters and Voltmeter.
4. Repeat the same process for unbalance load condition.
5. Switch off all the loads and supply.

Circuit Diagram:-

Basics of Electrical Engineering EED, SSEC, Bhavnagar Page No.


Observation Table:-

VR VY VB IR IY IB W1 W2 Total Power =
W1+W2
Balanced load

Unbalanced
load

Calculations:-

Basics of Electrical Engineering EED, SSEC, Bhavnagar Page No.


Conclusion:-

Basics of Electrical Engineering EED, SSEC, Bhavnagar Page No.

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