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Hydropower
Published in Robert Ehrlich, Harold A. Geller, John R. Cressman, Renewable Energy, 2023
Robert Ehrlich, Harold A. Geller, John R. Cressman
The rotational speeds of hydro turbines tend to be lower than either those of gas or steam turbines, typically being in the range of 60–720 revolutions per minute (rpm), although it is not unusual to have them as high as 1,500 rpm. Recall that the frequency of AC is 60 Hz (in the United States) and 50 Hz (in Europe). Thus, if the hydro turbine is being used to power a generator that produces electricity for the power grid, too low a turbine speed can be a major problem. You might think that a generator producing electricity having a 60 Hz frequency would need to be spinning at 60 revolutions/s = 3,600 rpm, but that assumes that the coil in the generator has just two magnetic poles. If many magnets are used (having a total of p poles), the coil could spin at a slower speed of 7,200/p rpm. However, a generator that is powered by a turbine spinning at only 60 rpm would be problematic since it would need an extremely large number of magnetic poles (120) in order to produce 60 Hz AC.
Alternating Current (ac) Electronics
Published in Dale R. Patrick, Stephen W. Fardo, Electricity and Electronics Fundamentals, 2020
Dale R. Patrick, Stephen W. Fardo
The phase angle (θ) of an ac circuit determines the power factor. Remember that the phase angle is the angular separation between voltage applied to an ac circuit and current flow through the circuit. Also, more inductive or capacitive reactance causes a larger phase angle. In a purely inductive or capacitive circuit, a 90° phase angle causes a power factor of 0°. The power factor varies according to the values of resistance and reactance in a circuit.
Lexicon
Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
alternating current: (Electrical) The type of electrical circuit in which the current constantly reverses (alternates) flow. The standard U. S. electrical service used in HVAC systems is single-phase or three-phase (polyphase) alternating current at 60 cycles per second.
Computational-Experimental Framework for Realizing a Novel Apparatus for Supercritical Water by Induction Heating
Published in Heat Transfer Engineering, 2023
Alessandro Montanaro, Luigi Allocca, Stefano Ranieri, Carlo Beatrice
IH consists in inducing electric currents (i.e., eddy currents) in a material to be heated, hereinafter referred to as “workpiece,” placed inside a multiturn coil (hereinafter “induction coil,” or simply “coil”). When an alternating frequency voltage is applied to an induction coil, an AC will begin to flow in the coil circuit, generating a time-varying magnetic field in its surroundings, characterized by the same frequency as the current in the coil (Ampere’s law). As stated by Faraday’s law, this variable magnetic field induces, in turn, eddy currents in the workpiece with the same frequency and opposite direction to the coil current, as shown in Figure 8. When eddy currents flow into the workpiece, the electric power is dissipated due to the Joule effect, producing the heating of the workpiece itself.
Implementation of zero current switch turn-ON based buck-boost-buck type rectifier for low power applications
Published in International Journal of Electronics, 2019
Nagi Reddy B, O. Chandra Sekhar, M. Ramamoorty
The AC–DC supply is generally used for various applications, such as battery charging for electric vehicles, lighting system, telecommunication systems, solar energy applications, LED drivers, battery energy storage systems (BESSs), appliances and inverters (Alonso, Vi˜na, Vaquero, Mart´ınez, & Os´orio, 2012, Singh, Singh, Chandra, Al-Haddad, Pandey, & Kothari, 2003, Tsorng-Juu, Chien-Ming, & Jiann-Fuh, 2009). For many of these applications, AC/DC converters require power factor correction (PFC) system to improve the input power factor with less harmonic distortion in the supply current. With the modern international power quality requirements, PFC methods have become more significant in the AC/DC converters, and a lot of research has been done on the PFC converters (Tsorng-Juu, Chien-Ming, & Jiann-Fuh, 2009; Singh, Singh, Chandra, Al-Haddad, Pandey, & Kothari, 2003).
Application of Behavioral Psychology in Clothing Design from The Perspective of Big Data
Published in Applied Artificial Intelligence, 2023
In the system, the OP284ES integrated operational amplifier chip is used to realize the signal buffer circuit, and the Multisim software simulation connection is shown in Figure 5. Simulation tests are used to evaluate the way individuals respond to and approach difficulties in real-world scenarios. XSC1 is a two-channel oscilloscope in Multisim software, and Multisim is a Windows-based board-level circuit simulation tool launched by National Instruments (NI) Co., Ltd. By using it, the schematic diagram of the circuit can be built interactively and the behavior of the circuit can be simulated. The OP284ES is a dual-channel, single-supply, 4 MHz bandwidth amplifier. It features rail-to-rail input and output, and is guaranteed to operate from+3 V to+36 V (or ±1.5 V to ± 1.8 V), and can operate from a single supply as low as+1.5 V. Furthermore, it is ideal for single-supply applications requiring both AC performance and precision DC performance. When audio and radio signals are sent across electrical cables, AC current is also present. AC current is typically utilized to power houses and businesses. In contrast, DC power is frequently utilized in low voltage applications where Batteries that power flashlights, various home appliances, and some industrial applications frequently use DC current. The combination of bandwidth, low noise, and accuracy makes it suitable for a variety of applications such as filters and instrumentation, including portable telecommunications equipment, power control and protection, and as amplifiers or buffers for sensors with wide output ranges. In addition, by taking advantage of rail-to-rail input and output swings, designers can build multistage filters in a single-supply system while maintaining a high signal-to-noise ratio. Multiple filter stages connected in series or parallel make up multistage filters. when you need to create a filter with an extremely narrow transition width or change the sample rate of a signal by a significant amount. The purpose of multistage filters is to shield the power line from other equipment-damaging electromagnetic interference caused by switching sources.