They are quite costly as compared to other instruments. Single phase electrodynamometer power factor meter. Electrodynamometer article about electrodynamometer by. The moving coil and pointer, which are attached to the coil, are suspended between and connected in series with the two field coils. Jun 08, 2019 dynamometer type wattmeter works on very simple principle and this principle can be stated as when any current carrying conductor is placed inside a magnetic field, it experiences a mechanical force and due to this mechanical force deflection of conductor takes place. Electrodynamometer type meters the electrodynamometer type meter differs from the galvanometer types we have just studied in that two fixed coils are used to produce the magnetic field instead of a permanent magnet. In movingiron instruments the movable system consists of one or more pieces of specially. Information and translations of electrodynamometer in the most comprehensive dictionary definitions. Note that, even though viscous damping as i just described is. They can be used in single phase, three phase three wire and three phase four wire system and are designed to be used in horizontal positions.
This type of instrument can be used either as an ammeter or as a voltmeter, but is generally used as a wattmeter. Be semesteriii electrical question bank electrical and. Nov 05, 2017 unlike a pmmc instrument, the electrodynamometer type instrument has nonuniform scale. Moving coil moving coil moves the pointer with the help of spring control instrument.
Mecog portable type instruments are electrodynamometer type instrument. Show the connections of an electrodynamometer wattmeter. Working forces are small as compared to moving iron type instruments. Wattmeter, energy meter, electrostatic instruments, rectifier type instruments, extension of ranges of voltmeters and ammeters. This instrument can measure ac as well as dc quantities.
Analog electrodynamometer portable type watt var power. Darsonval, electrodynamometer, and the moving iron. However, it is much more convenient to have an instrument that indicates power directly. Electrodynamometer definition of electrodynamometer by the. Some meter movements can be used for both ac or dc measurements, but in general, each meter movement is best suited for a particular type. An electrodynamometer is an instrument used for measuring the electric power. Darsonval, electrodynamometer, and the moving iron vane. The electrodynamometer type instrument is a transfer instrument. Electrodynamometer type instruments download as powerpoint presentation. Electrodynamic instruments are manufactured chiefly as portable, highly accurate instruments in three classes of precision. The nonuniform scale of this instrument can be explained by the equation of deflection.
The operation principle of this device lies in the. Electrodynamometer type wattmeter construction and working. Now let us look at constructional details of electrodynamometer type wattmeter. Construction and working principle of electrodynamometer type wattmeter. A transfer instrument is one which is calibrated with a d. Disadvantages of electrodynamic type power factor meters.
Electronic wattmeters are used for direct, small power measurements or for power measurements at frequencies beyond the range of electrodynamometer type instruments. Module 10 measuring instruments version 2 ee iit, kharagpur lesson 43 study of electrodynamic type. They can be used in single phase, three phase three wire and three phase four wire system and are designed to be used in. Now let us look at constructional details of electrodynamometer. This means that the torque in electrodynamometer instruments must have a finite value and unidirectional for ac and dc quantity unlike pmmc instruments.
Electrodynamometer wattmeter consists of two coils, pressure coil pc and current coil cc. Electrodynamic instrument article about electrodynamic. An electrodynamometer for measuring the torque of a motor. Maharashtra state board of technical education autonomous isoiec2700120 certified summer 2018 examinations subject code. Electrodynamometer article about electrodynamometer by the. The two coils are connected in different circuits for measurement of power. As we know that the deflection in electrodynamometer type ammeter and voltmeter is given as o ki2dmdo for ammeter and o kv2dmdo for voltmeter therefore, if dmdo is. Electrodynamometer electrodynamics type instruments the necessity for the a. Electrodynamometer type instruments alternating current. In this post we will be discussing the torque equation in. There are two general types of moving iron instruments namely.
Electrodynamometer type instruments pdf the electrodynamometer type instrument is a transfer instrument. The motor used for this purpose is called a wattmeter, and the instrument that can be applied as a wattmeter is known as a dynamometer, or sometimes as an electrodynamic instrument. Electrodynamometer definition is an ammeter or galvanometer in which the torque due to the reaction between two coils in series with each other is balanced by a spiral spring. Two movable coils are also used in the electrodynamometer meter. Differentiate between them with necessary diagrams. Encyclopedia article about electrodynamometer by the free dictionary. Moving iron instruments principle, operation and type. It essentially consists of the fixed and moving coil. Twootherinstruments were subjects of investigation also,thefirst no. Why doesnt it simply stay at zero feet position and oscillate there. Classification, absolute and secondary instruments, indicating instruments, control. Dynamometer type wattmeter working principle electrodynamometer.
The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. There is also a ferrodynamic type in which a magnetic circuit made of a ferromagnetic material is used to increase the strength of the magnetic field of the fixed coil. Information and translations of electrodynamometer in the most comprehensive dictionary definitions resource on the web. Following are the errors in the electrodynamometer type. Electrodynamometertype meters the electrodynamometertype meter differs from the galvanometer types we have just studied in that two fixed coils are used to produce the magnetic field. Apr, 2011 webers electrodynamometer webers electrodynamometer is a device used to measure electric power. Electrodynamometer type wattmeter electrical study app by. These instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Unlike a pmmc instrument, the electrodynamometer type instrument has nonuniform scale. Two identical pressure coils a and b pivoted on a spindle constitute the moving system. Repulsion or double iron type figure 1 attraction or singleiron type figure 2.
Electrodynamic type instruments are similar to the pmmctype elements except that the an electrodynamometer for use as a wattmeter is shown in fig. May 15, 2018 disadvantages of electrodynamic type power factor meters. The measuring quantity can be voltage, current, power and energy etc. Also state advantages and disadvantages of hotwire instruments. Webers electrodynamometer webers electrodynamometer is a device used to measure electric power. Aug 22, 2018 electrodynamic type instruments are similar to the pmmctype elements except that the an electrodynamometer for use as a wattmeter is shown in fig. Explain the working of attraction type and repulsion type moving iron instruments with neat diagrams. Discuss the construction and operation of an electrodynamometer type of 12 instrument. Generally instruments are classified in to two categories. Pressure coil a has a noninductive resistance r connected in series with it, and coil b has a highly inductive choke coil l connected in series with it. A dynamo meter type watt meter is used in various applications where the power or energy transfer has to be measured.
Following are the advantages of electrodynamometer type wattmeters and they are written as follows. Pg if there is no dc component to the force, then it will stay at x0, but your question relates to a. There are two types of coils present in the electrodynamometer. The faceplate can be lowered to provide access to the inside for coupling the. Definition of electrodynamometer in the dictionary. Electronic wattmeters are used for direct, small power measurements or for power measurements at frequencies beyond the range of electrodynamometertype instruments. The electrodynamometer movement meter has the same basic operating principle as the darsonval meter movement, except that the permanent magnet is replaced by fixed coils. Apr 24, 2018 electrodynamometer instruments are widely used as an ammeter, voltmeter and wattmeter. Classification, absolute and secondary instruments, indicating instruments, control, balancing and damping, constructional details, characteristics, errors in measurement, ammeters, voltmeters. The electrodynamometer includes a supporting structure and a stator mounted for rotation on the structure and having a. Moving iron instruments are generally used to measure alternating voltages and currents. This is a online courseware website for sns college students through this website student can access their materials. In electrodynamometer type wattmeter, moving coil works as pressure coil.
Electrodynamometer type instruments free download as powerpoint presentation. Electrodynamometer type wattmeter electrical study app. The fixed coil is split into two equal parts which are placed close together and parallel to each other. Power is measured by means of an electrodynamometer instrument. Hence moving coil is connected across the voltage and electrodynamometer wattmeter pdf and can moves freely. In movingiron instruments the movable system consists of one or more pieces of speciallyshaped soft iron, which are so pivoted as to be acted upon by the magnetic field produced by the current in coil. Electrodynamometer wattmeters these instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Labvolt series by festo didactic electrodynamometer. Moving iron instruments principle, operation and type, theory. The electrodynamometer movement meter has the same basic operating principle as the darsonval meter movement, except that the permanent magnet is. Electrodynamometer electrodynamics type instruments. Electrodynamometer definition of electrodynamometer by. Nonuniform scale of electrodynamometer type instrument. Calibration of electrodynamometer type instruments are highly affected by the changing the supply voltage frequency.
Hence, damping of any type would prevent any high amplitude and high frequency oscillations on the needle movement. Electrodynamometer wattmeter and low power factor lpf wattmeters are mostly similar in construction and operation, except for the following modifications are carried out in the. Power factor meters electrodynamometer type power factor. The basic principle was laid out in an 1848 paper by wilhelm weber 18041891.
Electrodynamometer instruments are widely used as an ammeter, voltmeter and wattmeter. Maharashtra state board of technical education autonomous. Before we study the internal construction of electrodynamometer wattmeter, it very essential to know the principle of working of electrodynamometer type wattmeter. A modern digital wattmeter samples the voltage and current thousands of times a second. Electrodynamometer type instruments an electrodynamometer type instrument is a moving coil instrument in which the operating field is produced by another coil which is fixed.
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