Brushless DC Motor Working

A DC machine actually has an AC current in the armature that is rectified by the commutator and brushes. Brushes eventually wear out, requiring maintenance, and they produce carbon dust and possibly arcing while operating. Nevertheless, the characteristics of DC machines are often desirable. With the advances in power electronics, …

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Single-Phase Induction Motor Working

single phase induction motor

Figure 1 shows the cross-sectional view of a single-phase induction motor. Consider the motor in Figure 1 at standstill. Current is applied to the windings, establishing two counter-rotating waves. As they sweep past the rotor bars they both try to start the machine but they cancel each other out. Thus, …

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Important Magnetic Units, Terms, Symbols, and Formulas

The following table presents important Magnetic Units, Symbols, and Their Formulas as a reference, or source of information. These formulas play a key role while dealing with magnetic circuits such as Transformers, Inductors. Term or quantity Symbol or abbreviation SI Unit and Formula Flux (lines) ϕ \[Weber\text{ }\left( Wb \right)=\frac{number\text{ …

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Solar Energy System Cost

A general method of calculation will start from the load energy requirements; determine the local insolation level and the worst month insolation and from this determine the sizing of the storage capacity. From this follows the array power and area, the battery capacity, and eventually the voltage regulator size respectively, …

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Electric Machine Efficiency and Losses

Regardless of which type of electric machine is chosen for a particular job, efficiency is important for several reasons. First, and perhaps most obvious, a less efficient machine will cost more to operate. Second, the losses in the machine are converted to heat, which raises the operating temperature of the …

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Synchronous Machine as Generator and Motor

Figure 1 shows a cross-sectional view of a salient-pole synchronous machine. The armature windings are shown as concentrated windings, but in reality, they would be distributed. Such machines can be operated either in Motor or Generator mode. Motor Operation For motor operation, a balanced three-phase set of voltages is applied …

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DC Machine Construction and Operation

Figure 1 shows elementary permanent- magnet machine. It is very similar to the AC machine; however, instead of a pair of slip rings to connect to the ends of the coil, there is a single split ring. Each end of the coil is connected to one-half of the ring, and …

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AC Motor and Generator Working Principle

Figure 1 shows a simple, single-turn, permanent- magnet machine. The single-turn coil is free to rotate between two magnetic poles of opposite polarity. Magnetic flux goes from a north pole to a south pole, so there will be magnetic flux in the region between the poles where the coil is …

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Properties of Magnetic Materials

Magnetic domains in a ferromagnetic material.

Consider the simple model of the atom in Figure 1. Electrons move around the nucleus like the earth around the sun. This electron motion is a small electric current, and anywhere there is a current, there is a magnetic field (moment). Electrons also spin around their axes like the earth. …

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Harmonics in Power System

Approximation to a square wave using the first five

Ideally, all voltages and currents in the power system should be single-frequency sinusoids (60 Hz in North America). The actual power system, however, contains voltage or current components, called harmonics, whose frequencies are integral multiples of the power system frequency. The second harmonic for a 60 Hz system is 120 …

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