Superposition Theorem Requirement: Power System is a complex network having number of voltage and current sources and number of loads. Now to analyze the network we need to find voltage/current at particular branch or load. In such cases calculations for thevenin's and norton's theorem becomes difficult. We can use superposition theorem to find voltage/current at any branch or load in complex network. In this theorem only one source considered at a time and total voltage/current is sum of voltage/current obtained by considering individual source. Statement of Superposition Theorem:
Question : An LVDT is connected to an amplifier of gain 250 the output terminals of which are connected to a 5 V voltmeter. The meter's scale can be read to 1/5th of a division and has 100 divisions in all. Given that a core displacement of 0.5 mm provides an output of 2 mV from the LVDT, find, 1. The sensitivity of the LVDT 2. The sensitivity of the whole system 3. The resolution of the instrument in centimeters Explanation : (a) Sensitivity of LVDT = Output voltage /displacement Sensitivity of LVDT = 2mV/0.5 mm = 4 mV/mm (b)Sensitivity of whole setup = amplification factor*sensitivity of LVDT Sensitivity of whole setup = 250*(4 mV/mm) = 1000 mV/mm (c) The resolution of the instrument in centimeters = minimum voltage that can be read by instrument /sensitivity of whole setup There are 100 divisions to measure upto 5V. So 1 division can read 5/100 = 0.05V Scale can read 1/5 of a division. So minimum voltage that can be read = 0.05/5 ...
Question: A step down DC chopper has a resistive load of R = 15 ohm and input Vdc = 200 V. When the chopper remain ON, it's voltage drop is 2.5V. The chopper frequency is 1 kHz. If the duty cycle is 50%, determine: a) Average output voltage b) RMS output voltage c) Chopper efficiency d) The effective input resistance of the chopper Answer: We can get answers directly by applying relevant formulas as shown below. (a) Average output voltage = 98.75 V (b) RMS output voltage = 139.6536 V (c) Chopper efficiency = 98.75% (d) The effective input resistance = 30.3799 ohm Additional information : Waveforms for step down chopper are shown below : For any queries regarding above solution please comment below. Thank you!
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