14-02-2012, 02:01 AM
hai.. i want source code and full details plz help me
:shy:
:shy:
14-02-2012, 02:01 AM
hai.. i want source code and full details plz help me
:shy:
14-02-2012, 10:01 AM
to get information about the topic power factor improvement using pic microcontroller full report ,ppt and related topic refer the link bellow https://seminarproject.net/Thread-automa...ull-report https://seminarproject.net/Thread-power-...ion?page=2 https://seminarproject.net/Thread-power-...?pid=51952 https://seminarproject.net/Thread-automa...ort?page=3 https://seminarproject.net/Thread-microc...ing-system
31-07-2012, 12:22 PM
Power factor
Power factor.doc (Size: 779 KB / Downloads: 58) Measuring of power factor Power factor in a single-phase circuit (or balanced three-phase circuit) can be measured with the wattmeter-ammeter-voltmeter method, where the power in watts is divided by the product of measured voltage and current. The power factor of a balanced poly phase circuit is the same as that of any phase. The power factor of an unbalanced poly phase circuit is not uniquely defined. A direct reading power factor meter can be made with a moving coil meter of the electrodynamics type, carrying two perpendicular coils on the moving part of the instrument. The field of the instrument is energized by the circuit current flow. The two moving coils, A and B, are connected in parallel with the circuit load. One coil, A, will be connected through a resistor and the second coil, B, through an inductor, so that the current in coil B is delayed with respect to current in A. At unity power factor, the current in A is in phase with the circuit current, and coil A provides maximum torque, driving the instrument pointer toward the 1.0 mark on the scale. At zero power factor, the current in coil B is in phase with circuit current, and coil B provides torque to drive the pointer towards 0. At intermediate values of power factor, the torques provided by the two coils adds and the pointer takes up intermediate positions. REACTIVE POWER: In any AC system the current, and therefore the power, is made up of a number of components based on the nature of load consuming the power. These are resistive, inductive and capacitive components. In the case of a purely resistive load, for example, electrical resistive heating, incandescent lighting, etc. the current and the voltage are in phase, that is the current follows the voltage. Whereas, in the case of inductive loads, the current is out of phase resistive loads and it lags behind the voltage. Except for a few purely resistive loads and synchronous motors, most of equipment and appliances in the present day consumer installation are inductive in nature, for example, inductive motors of all types, welding machines, electric arc and induction furnaces, choke coils and magnetic system, transformers and regulators, etc. in the case of a capacitive load the current and voltage are again out of phase but now the current leads the voltage. The most common capacitive loads are the capacitors installed for the correction of power factor of the load. The inductive or the capacitive loads are generally termed as the reactive loads. The significance of these different types of loads is that the active (or true or useful ) power can only be consumed in the resistive portion of the load , where the current and the voltage are in phase. The reactive component of load only consumes (watt less or). Reactive power which is necessary for energizing the magnetic circuit of the equipment (and is thus not available for any useful work). Inductive loads require two forms of power – working / active power (measured in kW) to perform the actual work of creating heat, light, motion, machine output, etc. , and reactive power (measured in kVAr) to sustain the electromagnetic field. To understand it better, we need to consider that there maybe two currents running through a circuit. One of these currents contains watts (watts produce work) and the other current contains no watts. Why do we need current with no watts (also referred to as watt-less current?) the answer is simple. The current known as watt-less current is required to produce the magnetic field around an-electric motor. If there was no watt-less current then an electric motor would not turn. The problems arise due to the fact that we can sometimes have too much watt-less current, in those cases we need to remove some of it. Non-sinusoidal components Non-linear loads change the shape of the current waveform from a sine wave to some other form. Non-linear loads create harmonic currents in addition to the original (fundamental frequency) AC current. Filters consisting of linear capacitors and inductors can prevent harmonic currents from entering the supplying system. In linear circuits having only sinusoidal currents and voltages of one frequency, the power factor arises only from the difference in phase between the current and voltage. This is "displacement power factor". The concept can be generalized to a total, distortion, or true power factor where the apparent power includes all harmonic components. This is of importance in practical power systems that contain non-linear loads such as rectifiers, some forms of electric lighting, electric arc furnaces, welding equipment, switched-mode power supplies and other devices. Active power factor correctors can be single-stage or multi-stage. In the case of a switched-mode power supply, a boost converter is inserted between the bridge rectifier and the main input capacitors. The boost converter attempts to maintain a constant DC bus voltage on its output while drawing a current that is always in phase with and at the same frequency as the line voltage. Another switch mode converter inside the power supply produces the desired output voltage from the DC bus. This approach requires additional semiconductor switches and control electronics, but permits cheaper and smaller passive components. It is frequently used in practice. For example, SMPS with passive PFC can achieve power factor of about 0.7–0.75, SMPS with active PFC, up to 0.99 power factor, while a SMPS without any power factor correction has a power factor of only about 0.55–0.65.
14-08-2012, 08:34 AM
Please send me more information on this topic chetan1908[at]ymail.com
14-08-2012, 11:22 AM
to get information about the topic "AUTOMATION IN POWER FACTOR IMPROVEMENT" full report refer the link bellow https://seminarproject.net/Thread-automa...ull-report
04-10-2012, 10:14 AM
send the power-factor-improvement-using-pic-microcontroller project.
thanks send power-factor-improvement-using-pic-microcontroller |
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