Guys, does anyone know the answer?
get the component of electric power which yields useful mechanical power output is known as from screen.
How Does A Generator Work?
Have you ever wondered how generators create electricity? Generators contain an engine and an alternator to produce alternating current.
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This article is about electromagnetic power generation. For electrostatic generators like the Van de Graaff machine, see Electrostatic generator. For devices to convert photons into electricity, see photovoltaic panel.
U.S. NRC image of a modern steam turbine generator (STG).
In electricity generation, a generator is a device that converts motive power (mechanical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all of the power for electric power grids.
The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators have many similarities. Many motors can be mechanically driven to generate electricity; frequently they make acceptable manual generators.
1 Terminology 2 History
2.1 Faraday disk generator
2.2 Jedlik and the self-excitation phenomenon
2.3 Direct current generators
2.4 Synchronous generators (alternating current generators)
3 Specialized types of generator
3.1 Direct current (DC)
3.1.1 Homopolar generator
3.1.2 Magnetohydrodynamic (MHD) generator
3.2 Alternating current (AC)
3.2.1 Induction generator
3.2.2 Linear electric generator
3.2.3 Variable-speed constant-frequency generators
4 Common use cases 4.1 Power station
4.2 Vehicular generators
4.2.1 Roadway vehicles
4.2.2 Bicycles 4.2.3 Sailboats
4.2.4 Electric scooters
4.4 Human powered electrical generators
4.5 Mechanical measurement
5 Equivalent circuit
6 See also 7 References
Early Ganz Generator in Zwevegem, West Flanders, Belgium
Electromagnetic generators fall into one of two broad categories, dynamos and alternators.
Dynamos generate pulsing direct current through the use of a commutator.
Alternators generate alternating current.
Mechanically a generator consists of a rotating part and a stationary part:
Rotor: The rotating part of an electrical machine.
Stator: The stationary part of an electrical machine, which surrounds the rotor.
One of these parts generates a magnetic field, the other has a wire winding in which the changing field induces an electric current:
Field winding or field (permanent) magnets: The magnetic field-producing component of an electrical machine. The magnetic field of the dynamo or alternator can be provided by either wire windings called field coils or permanent magnets. Electrically-excited generators include an excitation system to produce the field flux. A generator using permanent magnets (PMs) is sometimes called a magneto, or a permanent magnet synchronous generator (PMSG).
Armature: The power-producing component of an electrical machine. In a generator, alternator, or dynamo, the armature windings generate the electric current, which provides power to an external circuit.
The armature can be on either the rotor or the stator, depending on the design, with the field coil or magnet on the other part.
Before the connection between magnetism and electricity was discovered, electrostatic generators were invented. They operated on electrostatic principles, by using moving electrically charged belts, plates, and disks that carried charge to a high potential electrode. The charge was generated using either of two mechanisms: electrostatic induction or the triboelectric effect. Such generators generated very high voltage and low current. Because of their inefficiency and the difficulty of insulating machines that produced very high voltages, electrostatic generators had low power ratings, and were never used for generation of commercially significant quantities of electric power. Their only practical applications were to power early X-ray tubes, and later in some atomic particle accelerators.
Faraday disk generator
The Faraday disk was the first electric generator. The horseshoe-shaped magnet created a magnetic field through the disk . When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact , through the external circuit, and back into the center of the disk through the axle.
Mechanical Output Power
Mechanical Output Power
The rated mechanical output power from the WT is achieved at a particular speed of the wind.
From: Design, Analysis, and Applications of Renewable Energy Systems, 2021
Stirling EngineRotorsTurbinesWind TurbinesOrganic Rankine CycleElectric PotentialElectrical PowerOutput PowerPower Output
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K. Nakamura, in Power Ultrasonics, 2015
17.4.2 Discussion of motor performance
Mechanical output power plotted as a function of the weight for both commercialized traveling-wave rotary motors and DC servo motors is shown in Figure 17.41. The maximum possible input to bolt-clamped Langevin transducers is also indicated in Figure 17.17 (indicated by BLT), distributed around a line of 100 W/100 g. Output power per unit weight is constant at around 10 W/100 g for larger DC servo motors, although it decreases rapidly in smaller motors. The efficiency of conventional electromagnetic motors becomes too low for practical use when diameters are less than 10 mm. The output power and efficiency of ultrasonic motors remain moderate. This is one of the reasons why they are attractive as microactuators. However, the available power with BLT is much higher, and better performance may be expected from ultrasonic motors where sophisticated design transforms vibration to motor motion. The maximum torque is summarized against weight in Figure 17.42.
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Figure 17.41. Mechanical output power and the weight.
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Figure 17.42. Maximum torque and the weight of motor.
It is clear that ultrasonic motors provide higher torque than DC servo motors with the same weight. Because the working principle of the ultrasonic motor means that motor speed never exceeds vibration velocity, the vibration amplitude available with a transducer determines the maximum motor speed. Assuming the fatigue limit of piezoelectric ceramics to be 40 MPa under stress, a peak vibration velocity of 1.7 m/s is possible with a PZT ceramic plate transducer. However, the practical available vibration velocity is lower because of heat generated through the mechanical and dielectric loss occurring at high-amplitude operation. The maximum speed of an ultrasonic motor is therefore limited to < 1 m/s at best. The number of revolutions per second decreases in larger motors in reverse proportional to the diameter because the velocity at the circumference is subject to this limitation. It can therefore be seen that ultrasonic motors generally display low-speed and high-torque characteristics. It is necessary to develop a large transducer to obtain higher output power. However, if the diameter or width of the vibrator is increased, obtaining uniform vibration distribution over a wide output surface becomes difficult (Satonobu et al., 2000). To overcome this problem, the parallel operation of multiple transducers has been tested (Satonobu et al., 1997).
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Testing of electrical drive systems
Anthony J. Martyr, David R. Rogers, in Engine Testing (Fifth Edition), 2021
Most systems need a suitably ranged, analog voltage input to the measurement device inputs.
The basic requirement would be voltages and currents from each of the motor phases (typically 3 or 6 at the time of writing) on the AC side. For determining motor drive system efficiency, it would be necessary to measure DC voltage and current on the inverter supply side. While for motor efficiency tests, motor speed and torque values from a dynamometer are essential. A system overview is given in Fig. 12.6.
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Figure 12.6. Overview of powertrain motor system typical measurement points.
For in-vehicle measurement, access to the system for measuring physical speed and torque is much more difficult. These in-vehicle measurements are undertaken later in the development cycle, where the control system is calibrated such that speed and torque are derived in the controller and available on the controller bus network [Controller Area Network (CAN), etc.]. Motors are often fitted with rotational positional sensors (known as resolvers), but the signal processing for this type of encoder is not generally considered in the external power analysis measurement system. More important is the ability to detect an electrical cycle period, from which result values for that given cycle (or half cycle) can be calculated. This is normally considered in the measurement software and involves quite sophisticated algorithms to detect each phase accurately—irrespective of speed or change of speed. This is the most challenging aspect and the main difference between standard power analyzers and those which are developed for automotive system measurement (where a wide range of frequencies is encountered in the motor drive system).
Other measurements of interest are temperatures—motor winding and rotor temperatures for component protection function calibration and validation of simulation models. Battery and inverter temperatures are necessary for the optimized calculation of energy balance, and simulation validation.