Electrical circuit 2 ( Capacitor , Conductor, Inductor ,Power factor)
Download as PPTX, PDF0 likes67 views
The document covers various electrical components, primarily capacitors and inductors, explaining their functions and classifications, including fixed and variable capacitors. It also discusses power concepts in AC circuits such as instantaneous, real, reactive, and apparent power, along with the power factor and its implications for circuit performance. Additionally, it highlights the importance of power factor correction and provides insights into measuring AC power using a wattmeter.
Electrical circuit 2 ( Capacitor , Conductor, Inductor ,Power factor)
- 2. Capacitor A device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator.
- 3. Capacitor An electrolytic capacitor (e-cap) is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A fixed capacitor is constructed in such manner that it possesses a fixed value of capacitance which cannot be adjusted. A fixed capacitor is classified according to the type of material used as its dielectric, such as paper, oil, mica, or electrolyte.
- 4. Capacitor A variable capacitor is a capacitor whose capacitance may be intentionally and repeatedly changed mechanically or electronically.
- 5. Capacitor
- 6. Inductor A component in an electric or electronic circuit which possesses inductance.
- 7. Inductor
- 8. Instantaneous power Instantaneous power p(t) is defined as the product of instantaneous voltage v(t) and instantaneous current i(t). Assuming the sinusoids waveforms v(t) = Vm cos (ω t + θ v ) and i(t) = Im cos (ω t + θi ) represent the voltage and current, then it can be shown:
- 9. Active Power Instantaneous power to a load is p = v • i. In an ac circuit ◦ p may be positive sometimes and negative other times Average value of the power, P ◦ Real power
- 10. Active Power Average value of instantaneous power, real power, active power, and average power mean the same thing.
- 11. Reactive Power During times when p is negative, power is being returned from load This can happen for inductive or capacitive loads
- 12. Apparent Power Power to a load is VI If load has both resistance and reactance ◦ Product is neither the real power nor the reactive power, but a combination of both
- 13. Apparent Power This is called the apparent power, S S = VI = I2Z = V2/Z Units are volt-amperes (VA)
- 14. Apparent Power
- 15. Relationship Between P,Q, and S P, Q, and S are related by the “power triangle” S Q P 22 QPS
- 16. Active and Reactive Power Equations P = VI cos = S cos Q = VI sin = S sin V and I are RMS values is the phase angle between V and I Q is positive for inductive circuits and negative for capacitive circuits
- 17. Power Factor Ratio of real power to apparent power is called the power factor, Fp Fp = P/S = cos Angle is angle between voltage and current
- 18. Power Factor For pure resistance = 0° For inductance, = 90° For capacitance, = -90° For a circuit containing a mixture, is somewhere between 0° and 90°
- 19. Power Factor Unity power factor ◦ For a purely resistive circuit, the power factor will be one For load containing resistance and inductance ◦ Power factor will be less than one and lagging ◦ Current lags the voltage
- 20. Power Factor For a circuit containing resistance and capacitance ◦ Fp is less than one and is leading
- 21. Why Equipment Is Rated in VA A highly reactive load ◦ May seem to require a small amount of power while requiring a large current Equipment is rated in VA to prevent overloading the circuit
- 22. Why Equipment Is Rated in VA Size of electrical apparatus required by a load ◦ Governed by its VA requirements
- 23. Power Factor Correction A load with a small power factor can draw a large current Can be alleviated by ◦ Cancelling some or all reactive components of power by adding reactance of opposite type to the circuit This is power factor correction
- 24. Power Factor Correction Industrial customers may pay a penalty for low power factors due to large currents required for highly reactive loads
- 25. AC Power Measurement To measure power in an ac circuit you need a wattmeter Meter consists of ◦ Current-sensing circuit ◦ Voltage-sensing circuit ◦ Multiplier circuit ◦ Averaging circuit
- 26. AC Power Measurement This will measure load voltage and current and find the product and the angle between these
- 27. Thank you for your kind attention Question ???
Editor's Notes
- #3: a