MEASUREMENT OF REACTIVE POWER OF STAR AND DELTA CONNECTED BALANCED LOADS

AIM: To measure active power of star and delta loads by single wattmeter method.

APPARATUS:

SL.NO EQUIPMENT RATING TYPE QUANTITY1 Rheostats 300Ω/1.7A WW 32 Capacitors 25µF Parallel plate 33 Ammeter (0-1A) MI 14 voltmeter (0-600V) MI 15 wattmeter (600V,2.5A) UPF 16 3-Φ variac 415/(440-470)V ----------- 17 Connecting wires ------------ ----------- As per required

CIRCUIT DIAGRAM:

(0-20)A MC

R

50Ω

(0-600V) 50Ω

MI

Y 50Ω

B

600V,2A,UPF

(0-20)A MC

R

200Ω

(0-600V) 200Ω

MI

200Ω

Y

B

600V,2A,UPF

PROCEDURE:

1. Connect the circuit as per the circuit diagram.

2. Make sure that the knob of three phase variac is in minimum voltage position.

3. Now feed variac and apply different voltages to three phase load.

4. Now note down readings of voltmeter, ammeter and wattmeter without parallax error.

5. Disconnect the circuit after the experiment is over.

OBSERVATION TABLE:

STAR CONNECTED:-

SL. NO VL(V) IL(A) W(WATTS) SINΦ COSΦ REACTIVE POWER (√ 3W ¿

123456

DELTA CONNECTED:-

SL. NO VL(V) IL(A) W(WATTS) SINΦ COSΦ REACTIVE POWER (√ 3W ¿

123456

PRECAUTIONS:

1. Avoid making loose connections.2. Readings should be taken carefully without parallax error.3. Handle instruments with care and operate smoothly.

RESULT: Measurement of three phase power with single wattmeter is hence verified.