Three phase power measurement using two wattmeter method
AIM:
To measure the power in 3 -phase balanced star connected load and to determine the power factor.
APPARATUS REQUIRED:
- Wattmeter 2.50 A, 600V 2 No’s
- Ammeter 0 – 2.5 A M/I Type 1 No’s
- Voltmeter 0 – 500 V M/I type 1No’s
- Lamp load
- Connecting wires.
THEORY:
The following methods are used for the measurement of three phase power.
- One Wattmeter Method : For balanced Load
- Two Wattmeter Method : For balanced Load / Unbalance Load
- Three Wattmeter Method : For balanced Load / Unbalance Load
PROCEDURE:
- Connect the circuit as shown in the Figure to measure the power in star connected load.
- Check the circuit and switch on 3Φ supply switch.
- Take the readings of the ammeters, voltmeters and wattmeter’s connected in the circuit.
- Total power measured is given by (w1 + w2) watts.
- Calculate the power by formula P = √3VLILcosΦ
- Compare the two results.
- Repeat the experiment for different loads
CIRCUIT DIAGRAM :
OBSERVATION TABLE:
Lamp load per phase | IL ( A) | VL (V) | W1 (Watts) | W2 (Watts) | P= W1 + W2 | Φ=tan-1 {√3(w2 – w1)] /(w2 + w1)} | Power factor =Cos Φ | P = √3VLILcos Φ | |
Star Connection | |||||||||
FORMULA USED:
- Real power,P = w1 + w2
- Reactive power,Q = √3 (w1 – w2 )
- Tan Φ = √3 (w1 – w2 )/ (w1 + w2)
- Power factor = cosΦ
RESULT:
Thus the power in 3 -phase balanced star connected load is measured and determined the power factor
Recent Comments