Question

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Answer 1

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Practical Significance

In the industry environment Electrical Engineering diploma graduate are expected to analyze basic parameters like voltage, frequency, time period etc. for R-C series circuits. Therefore this practical will help you to acquire necessary skills.

Competency and Practical Skills

This practical is expected to develop the following skills for the industry identified competency ‘Maintain electrical systems applying AC and DC circuit fundamentals’:

i. Select relevant range of meters.

ii. Select suitable resistance and capacitance.

Relevant Course Outcome(s)

1. Troubleshoot problems related to single phase A.C R-C series circuits.

Practical Outcome

1. Use voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit. Draw phasor diagram.

Relevant Affective domain related Outcome(s)

1. Follow safety electrical rules for safe practices.

Minimum Theoretical Background

Impedance of R-C series circuit:

Impedance of R—C series circuit is the phasor sum of resistance and capacitive reactance.

Impedance Triangle:

 

Phasor diagram of R-C series circuit:

It is the diagram showing the phasor relationship between voltages VR, VC and V with respect to current I.

AC power for R-C series circuit:

AC power is the phasor sum of active power (P), reactive power (Q) and apparent power (S).

 

Practical set-up / Circuit diagram / Work Situation

 

Resources Required

Precautions

1. Ensure proper earthing to the equipment.

2. Ensure the power switch is in ‘off condition initially.

3. Ensure the output voltage of the variac should be zero.

Procedure

1. Make sure that capacitor is discharged.

2. Connect the circuit as per circuit diagram.

3. Set the rheostat for maximum resistance.

4. Set the variac to zero output and switch on a.c. mains.

5. Apply a suitable voltage adjusting the variac, so that a suitable current flows. Measure and note the voltages across R and C, current and power through it. Also measure the output voltage of variac.

6. Repeat the above procedure for different output voltages of variac/varying R/varying C.

7. Reduce the autotransformer position to zero and switch OFF the supply.

8. Draw the phasor diagram.