# Measure Three Phase Power

Aim:- To measure three phase power and power factor in three phase circuit by single-phase wattmeter under;

1.     Calculate the three phase power for balance load condition

2.     Calculate the three phase power for unbalanced load condition.

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Apparatus Required:-

 S. No. Name of Equipment Type Range Quantity 1. Wattmeter Dynamometer 5A, 600V 1 2. Voltmeter MI 0 – 500V 1 3. Ammeter MI 0 – 5A 1 4. Three Phase Load  arrangment - - 1 5. Lamp load Resistive 250V, 1KW 1

Theory:- Power consumed by three plisse balanced or unbalanced load connected in star or delta can be measured by using twa perly connected in the cicuit. The current coil of the wattmeter's are connected in series with the load in any iwo likes whereas the two pressure coils are connected between these lines and the third line as shown in below figure.

Circuit Diagram:-

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

4.      Repeat the same process for unbalance load condition.

5.     Switch OFF all the loads and supply.

Observation Table:-

 S. No. Condition IR IY IB VR VY VB M.F. W1 W2 1. Balanced  Load 1.6 1.6 1.6 235 235 285 2 280 280 2. Unbalanced Load 1.7 2.6 2.7 280 245 185 2 290 520

Calculation:-

Load Count of Voltmeter = 10V

Load Count of Ammeter = 0.1A

M.F. =

P.M. = W1+W2 = 1620 W

P.C. = VAIA + VBIB+ VCIC = 1612.5 W

% Error = 6.46 %

P.M. = W1+W2 = 1120 W

P.C. = VAIA + VBIB+ VCIC = 1128 W

% Error = 0.7 %

Precautions:

1.     All the connections should be tight and clean.

2.     The readings in ammeters should not exceed the current ratings of wattmeters.

3.     With negative deflection in wattmeter the connection should be reversed.