Aim: To measure power in a single phase AC circuit using wattmeter by RLC loading. APPARTUS REQUIRED: SL.No Name of the Apparatus Range / Type Quantity 1 Voltmeter (0-300V) MI 1 No. 2 Ammeter (0-10A) MI 1 No. 3 Wattmeter 300V,10A,LPF 1 No. 4 RLC Load 5kW 1 No. 5 Connecting Wires 1/18 SWG As per requirement THEORY: Power in an electric circuit can be measured using a wattmeter. A wattmeter consists of two coils, namely current coil and pressure coil or potential coil.
The current coil is marked as ML and pressure coil is marked as CV. The current coil measure the quantity that is proportional to the current in the circuit the pressure coil measures quantity that is proportional to the voltage in the circuit. The given wattmeter is loaded by direct loading. The ammeter is connected in series to the wattmeter. Since the same current flows in both the coils, the current and voltage across the circuit are constant. The power consumed by the load is measured using the wattmeter and calculated using the relation given below.
= Actual Power / Apparent Power PROCEDURE: 1. Connect the circuit as shown in the circuit diagram. Initially no load is applied. Autotransformer is set to minimum voltage position before switching on the power supply. Set the rated voltage by using the autot ransformer. Measure and record t he values of voltmeter, ammeter and wattmeter on no load condition.
Also carefully note the multiplication factor of the wattmeter that is mentioned in the wattmeter itself. Apply t he load by adjusting RLC load. Measure and record the values of voltm eter, ammeter and wattmeter. Repeat the steps 5 and 6 until the ammeter reading reaches 10A. After taking all the readings, reduce the load slowly to the minimum and bring the voltage to minimum in the autotransformer. Switch off the power supply.
Installation Electrical Laboratory Manual
Laboratory Electrical Safety
Calculated the Indicated po wer by the given formula. Calculate the power factor by the gi ven formula.