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Direct Current (dc) Electronics
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
Water pressure is needed to force water along a pipe. Similarly, electrical pressure is needed to force current along a conductor. Water pressure is usually measured in pounds per square inch (psi). Electrical pressure is measured in volts (V). If a motor is rated at 120 V, it requires 120 V of electrical pressure applied to the motor to force the proper amount of current through it. More pressure would increase the current flow and less pressure would not force enough current to flow. The motor would not operate properly with too much or too little voltage. Water pressure produced by a pump causes water to flow through pipes. Pumps produce pressure that causes water to flow. The same is true of an electrical energy source. A source such as a battery or generator produces current flow through a circuit. As voltage is increased, the amount of current in the circuit is also increased. Voltage is also called electromotive force (EMF).
Essentials of Electricity
Published in Anthony J. Pansini, Guide to Electrical Power Distribution Systems, 2020
The relationship of current, voltage, and resistance must be considered in every electric circuit. Direct current will flow only in a closed circuit, one which provides a continuous conducting path from the negative to the positive terminal of the voltage source. The way the electromotive force (emf), E, is distributed through the circuit and the relationships of voltage, current, and resistance, are contained in Ohm’s law, which states that the current in an electric circuit is directly proportional to the voltage and inversely proportional to the resistance.
Electrical Fundamentals
Published in Majid Jamil, M. Rizwan, D. P. Kothari, Grid Integration of Solar Photovoltaic Systems, 2017
Majid Jamil, M. Rizwan, D. P. Kothari
A change in electric potential between two points in an electric circuit is called a potential difference. The electromotive force (emf) provided by a source of energy such as a battery or a generator is measured in volts.
Flow channel optimisation of iodine zinc flow battery modelling
Published in International Journal of Sustainable Energy, 2023
Zhiqiang Liu, Jie Wen, Bin Yang
Positive electrode: Negative pole: Total reaction: When there is current flow in the iodine zinc flow battery, the equilibrium potential depends on the ion and proton concentrations participating in the reaction in the electrolyte of the iodine zinc flow battery, which can be represented by the Nernst equation: where and are the electromotive force of the reaction between the negative and positive poles, and the standard electromotive force is . R is the molar gas constant, Ts is the stack temperature, F is the faraday constant. and are the molar concentrations of iodide ion and triiodide ion in the stack, respectively, is the molar concentrations of zinc ion in the stack. is the activity coefficient of various ions. Since of different ions can be considered to cancel each other roughly, the following equation is obtained:
Comparative analysis of super high-speed permanent magnet generator electromagnetic and temperature fields with the PWM and uncontrolled rectifiers
Published in EPE Journal, 2020
Hongbo Qiu, Xifang Zhao, Yanqi Wei, Bingxia Tang, Ran Yi, Guangzhao Cui, Cunxiang Yang
In order to verify the accuracy of the analysis method, the SHSPMG prototype was tested. Figure 3 shows the test platform of this SHSPMG in the laboratory. In addition, based on the external circuit in Figure 2, the output electric voltage and current of SHSPMG are calculated by finite element method. The test data and simulation results are shown in Table 2. From Table 2, it can be seen that the experimental data are in good agreement with the finite element calculation results. In addition, Figure 4 shows the electromotive force waveforms obtained from the test and the finite element method. By comparing the electromotive force waveform obtained by the two methods, it can be seen that the two electromotive force waveforms are in agreement.
Low voltage ride through enhancement in DFIG based WECS by hybrid method
Published in International Journal of Electronics, 2022
Angala Parameswari G, Habeebullah Sait
Dramatically, these circumstances change in the case of voltage dip. For instance, the voltage dip causes the stator with short circuited when the time is zero. In Equations (17) and (18), the derivative of stator flow denotes zero by disregarding the less voltage dip at stator resistance. By then, flux remains constant and the rotation is stopped. Since the stator flux is adjusted with the stator, it corresponds to speed in terms of rotor winding with rotor speed. Then, the electromotive force is expressed as