What is Power factor?
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The document discusses power factor generation in both DC and AC systems, highlighting solar cells as a method for generating DC and alternators for AC. It explains how resistive, inductive, and capacitive loads interact with voltage and current, emphasizing phase differences and their impact on power efficiency. Additionally, it outlines the characteristics of various loads, including pure resistive, inductive, capacitive, and their combined forms.
What is Power factor?
- 1. Power Factor Generation of DC Generation of AC Resistive Load with AC Capacitive Load with AC Different value of PF Conclusion Inductive Load with AC ф P=V I Cos ф
- 2. Power Factor Generation of DC Generation of AC Resistive Load with AC Capacitive Load with AC Different value of PF Conclusion Inductive Load with AC • Most popular method to generate Direct Current (DC) is by using a Photo voltaic cell (solar cell). • Solar cell is similar in construction with PN diode but it has large x section then the length.
- 3. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • When sun light falls on N-Layer its majority charge carrier i.e. electrons get excited and feels attraction from P-layer, crosses the junction and comes in to the P-layer. • Due to the change in electron concentration in P-Layer and N-layer, potential difference appears across cell. Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 4. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • This potential difference i.e. voltage always has same polarity i.e “Positive potential” at N-side and “Negative potential” at P-side and almost of constant magnitude as sunlight cannot vary suddenly and this voltage is said to be “Direct Voltage”. • When electric load for example a bulb is connected across the cell an electric current of same nature as voltage flows through the load and the current is said to be “Direct Current” Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 5. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • Wave form of Direct Voltage and Direct Current is shown in fig. • In case of DC, the voltage and current never changes its direction although magnitude can vary (not sudden) P = V I P = I2 Ror or DC source and Resistive Load Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 6. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • Although Solar cells are getting popular these days, but still maximum part of world’s electrical energy produced through alternating current generators (Alternators). • Alternators uses very common phenomenon to produce electric voltage i.e by moving a magnetic field against stationary electrical conductor (in form of multi-turn winding). Thus the voltage produced varies in sinusoidal fashion Generation of Alternating Voltage Waveform of Alternating voltage Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 7. Power Factor Generation of DC Generation of AC Resistive Load with AC Capacitive Load Different value of PF Conclusion Inductive Load with AC • Although Solar cells are getting popular these days, but still maximum part of world’s electrical energy produced through alternating current generators (Alternators). • Alternators uses very common phenomenon to produce electric voltage i.e by moving a magnetic field against stationary electrical conductor (in form of multi-turn winding). Thus the voltage produced varies in sinusoidal fashion DC source and Resistive Load
- 8. Power Factor Generation of DC Generation of AC Resistive Load with AC Different value of PF Conclusion • When an alternating voltage (waveform shown in blue color fig 2) is applied across an electrical load of pure resistive nature (symbolically represented in fig 1) such as electric bulb or electric iron etc. Then, current will have the same nature (waveform shown in red color fig 2). • There is no phase difference between Voltage and Current as both attend Positive, negative and zero value at same time i.e. both the oscillating quantities, oscillate in same phase and power always attend positive value which signifies AC source and Resistive load Power, Voltage and Current waveform for Resistive load Capacitive Load with AC Inductive Load with AC
- 9. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • Practically many electrical loads comprise of slight inductive nature due to presence of winding or coils: like electrical fan, tube light with chock coil, washing machine and most of the industrial equipments. • In case of inductive load; current lags in phase with voltage due to which average useful power is less as compare to if it would be only resistive load. Due to, some part of power get returned as can be seen form waveform (yellow color). AC source and Resistive-Capacitive (RC) load Voltage and Current waveform for Resistive-Capacitive (RC) load Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 10. Power Factor Generation of DC Generation of AC Different value of PF Conclusion • Few special loads can posses capacitive nature due to presence of parallel plates, due to capacitance the load oppose change in voltage and hence voltage lags behind current in phase. • Again due to phase difference the average power decreases. As, a part of it get returned which can be seen from waveform (yellow color) AC source and Resistive load Voltage and Current waveform for Resistive load Resistive Load with AC Capacitive Load with AC Inductive Load with AC
- 11. Power Factor Generation of DC Generation of AC Different value of PF Conclusion Resistive Load with AC Capacitive Load with AC Inductive Load with AC Resistive load Voltage and current In same phase Ɵ = 0° P = V I cos 0° P = V I Inductive Load Current Lags Voltage by 90° Ɵ = 90° (lagging) P = V I cos 90° P = 0 Capacitive load Current lead Voltage by 90° Ɵ = 90° (lead) P = V I cos 90° P = 0
- 12. Power Factor Generation of DC Generation of AC Different value of PF Conclusion Resistive Load with AC Capacitive Load with AC Inductive Load with AC Resistive-Inductive Load (R-L Load) Current lags voltage by angle Ɵ 0° < Ɵ < 90° P = V I cos Ɵ Resistive-Capacitive Load (R-C Load) Current lead voltage by angle Ɵ 0° < Ɵ < 90° P = V I cos Ɵ