Basic Electrical Installation Work

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7, p.) defined the cosine the phase angle between the current and voltage: p.c.) defined the cosine the phase angle between the current and voltage.2 2. cos R T φ R Z V V The electrical power circuit the product the instantaneous values of the voltage and current. Inductors store energy magnetic field and capacitors electric field.f.2 Ω ∴ Ω Ω For (c): I V Z I (A) 230 V 113. circuit voltage and current are phase.c.05 113.f.f.05 π Ω ∴ π Ω For (b): Z X Z 2 2 2 ( ) (100 (53. . circuit the power consumed given the product the volt- age and current, because d. can seen that the power waveform reverses every quarter cycle, indicating that energy alter- nately being fed into and taken out the inductor and capacitor. cos φ Definition Power factor (p.03A ∴ Ω Power and power factor Power factor (p.f. In electric circuit more power taken from the supply than fed back into it, since some power dissipated the resistance the circuit, and therefore: P ) In any d.8 Waveform for the a. Power Power I I V V Pure inductor Pure capacitor FIGURE 10. also equal to: p.Alternating current theory and electrical machines 201 For (a): X fC X C C 6 1 2 ( ) 1 2 50Hz F 53.This shows that inductors and capacitors store energy during one part of the voltage cycle and feed back into the supply later the cycle.8 shows the voltage and current waveform for pure inductor and pure capacitor.f.c. is said leading. If the current lags the voltage shown Fig.5, say that the p. 10.f.6, the p. The power waveform obtained from the product and every instant the cycle. 10. is lagging, and the current leads the voltage shown Fig. When con- sidered over one complete cycle, the positive and negative portions are equal, showing that the average power consumed pure inductor capacitor is zero. power purely inductive and purely capacitive circuits. 10. From the trigonometry the impedance triangle shown in Fig. Figure 10.f