Before we study the internal construction of electrodynamometer type wattmeter, it is essential to know the working principle of electrodynamometer type wattmeter. The main principle of working of weston type frequency meter is that when an. Electrodynamometer type instruments construction and operation. It uses for measuring the power of both the ac and dc circuits. The electrodynamometertype meter differs from the galvanometer types in that two fixed coils are used to produce the magnetic field instead of a permanent magnet. These instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. The electrodynamometer type meter differs from the galvanometer types in that two fixed coils are used to produce the magnetic field instead of a permanent magnet.
Given below is the circuit diagram for the weston type frequency meter. An instrument which measures electrical energy in watt hours is essentially a wattmeter which accumulates or averages readings. The weston frequency meter is a moving iron instrument used for measuring the unknown frequency of a signal. The two coils are connected in different circuits for measurement of power. A transfer instrument is one which is calibrated with a d. It works on the phenomenon of resonance hence it is also called as mechanical resonance type frequency meter 1. Now let us look at constructional details of electrodynamometer type wattmeter.
The deflection of the pointer is directly proportional to the power flows through it. Many are instruments of the deflection type, ordinarily used for measuring low frequencies but capable of being used for frequencies as high as 900 hz. The instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the electrodynamometer wattmeter. Electrodynamometer type, induction type, single phase and three phase wattmeter, compensation, energymeters. A limited amount of current flows through the moving coil so as to avoid heating. Frequency meters measure repetitions per unit of time frequency and display it using a needle or graphic pointer. Instruments with moving coils can be calibrated for direct current or power frequency currents up to a few hundred hertz. The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. In order to construct a circuit diagram we need two coils, three inductors and two resistors. Oct 16, 2014 introduction to frequency meter universal counter need of frequency meter a digital frequency meter is a generalpurpose, basic, digital counter for measuring, setting, and monitoring frequencies, for counting random events, and for industrial counting applications. All alternating voltage sources are generated at a set frequency or range of frequencies. Single phase induction type energy meter, driving and braking torques.
Construction types of wattmeter dynamometer type wattmeter induction. Construction of weston frequency is as compared to ferrodynamic type of frequency meter. Also, on analog wattmeters, the potential coil carries a needle that moves over a scale to indicate. Performance improvement of reed type frequency meter. There are two types of coils present in the electrodynamometer.
Mar 29, 2017 for the love of physics walter lewin may 16, 2011 duration. Electrodynamometer electrodynamics type instruments. Jun 15, 2018 the main principle of working of weston type frequency meter is that when an current flows through the two coils which are perpendicular to each other, due to these currents some magnetic fields will produce and thus the magnetic needle will deflects towards the stronger magnetic field showing the measurement of frequency on the meter. The instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the electrodynamo meter wattmeter. The meter was inserted in the line under test and a detector was also connected. Electrodynamic instrument a measuring instrument whose operation is based on. In this post we will be discussing the torque equation in. The main principle of working of weston type frequency meter is that when an current flows through the two coils which are perpendicular to each other, due to these currents some magnetic fields will produce and thus the magnetic needle will deflects towards the stronger magnetic field showing the measurement of frequency on the meter. A ratiometer type frequency meter consists of a ratio meter. But in these instruments, the operating field is produced by the fixed coil instead of a permanent magnet. Electrodynamometer type wattmeter working principle.
Power factor meter working principle the basic working principle of power factor meter is similar to that of dynamometer type wattmeter i. Frequency meter inductor electromagnetic induction scribd. They are used as wattmeters, voltmeters and with some modification as power factor meters and frequency meters. The general circuit diagram of single phase electrodynamometer power factor meter is given below. Because of the inductance, the current of the pressure coils lags behind the voltage. Dynamometer and induction type energy meterinduction typeinstrument transformers. The electrodynamometer is often considered the basic indicating meter for low frequency sinusoidal measurements. Other frequency measuring instruments like digital, ferrodyanmic type frequency meter, electrodynamometer type frequency meter are also available in. Industrial frequency meters are used in radio frequency rf and microwave applications to tune transmitters and otherwise display rapidlychanging frequencies. Dynamometer type wattmeter electrical technology youtube. In electrodynamometer type power factor meter there are further two types on the basis of supply voltage 1 single phase 2 three phase.
Study of ammeter, voltmeter and wattmeter connections. This ratio meter gives a relationship between the current ratio and the deflection. When the frequency of the signal varies from standard frequency, the current distribution across the coils becomes changes. Type of frequency meters mechanical resonance type frequency meter, electrical. A frequency meter provides a means of measuring this frequency.
Which type of instrument is preferred for power measurement. Electrodynamometer type instruments pdf the electrodynamometer type instrument is a transfer instrument. They are used as wattmeters,varmeters and with some modification as power factor meters and frequency meters. Apr 24, 2018 electrodynamometer instruments are widely used as an ammeter, voltmeter and wattmeter. Single phase electrodynamometer power factor meter. 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. Apr 08, 2018 the shape of scale of this instrument depends on the variation of dmdo i. Static part consists of mainly one threelimbed transformer and a lamp. Power factor meters electrodynamometer type power factor meter.
This means that the torque in electrodynamometer instruments must have a finite value and unidirectional for ac and dc quantity unlike pmmc instruments. 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 instead of a permanent magnet. This principle is utilized in electrodynamometer type instrument. Visualizing high frequency nontransient waveform xvii.
The basic principle was laid out in an 1848 paper by wilhelm weber 18041891. Construction and working principle of electrodynamometer type wattmeter. Nov 30, 2015 an electrodynamo meter type wattmeter has two coils. The device consists of a pair of fixed coils, known as current coils, and a movable coil known as the potential coil the current coils are connected in series with the circuit, while the potential coil is connected in parallel. Electrodynamometer definition of electrodynamometer at. Dynamometer type wattmeter working your electrical guide. The fixed coils or field coils are connected in series with the load and so carry. Moving coil moving coil moves the pointer with the help of spring control instrument.
The current coil, which is connected in series, is made up of thick wires of few turns and is divided into two identical parts as shown in the figure. This instrument can measure ac as well as dc quantities. Electrodynamometer weston type ratiometer type saturable core. Power factor meters electrodynamometer type power factor. The 536a measures frequencies in the range of 940 mhz to 4. 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. Dec 24, 2019 electrodynamometer type wattmeter electrical study app by saru tech. Measurement of the frequency in alternating current circuits, for any type of wave shape and under adverse environmental and physi cal conditions. Electrodynamometer type instruments construction and. The fixed coils or field coils are connected in series with the load and so carry the. Electrodynamometer wattmeters these instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters.
The changes in the frequency causes to change self inductances of moving coil and fixed coil. Frequency meter free download as powerpoint presentation. Electrodynamometer definition of electrodynamometer by the. Digital electronic instruments measure many parameters and can be used where a wattmeter is needed. The number of pulses counted at the output terminal during. Electrodynamometer type instruments alternating current. In electrodynamometer type wattmetermoving coil works as pressure coil. The electrodynamometer is often considered the basic indicating meter for lowfrequency sinusoidal measurements. Jun 08, 2019 before we study the internal construction of electrodynamometer type wattmeter, it is essential to know the working principle of electrodynamometer type wattmeter 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. Electrodynamic frequency metermoving coil frequency meters are ratiometer type of.
Electrodynamometer type wattmeter construction and working. Power factormeter synchroscope frequency meterdigital voltmeter. Hi friends, in this article, i am discussing the dynamometer type wattmeter working principle and related information, if you are interested in it then you at the right place these are basically moving coil instruments. 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. Electrodynamometer definition, an instrument that uses the interaction between the magnetic fields produced by the currents in two coils or sets of coils to measure current, voltage, or power. Electrodynamometer types of instruments are used as a. A frequency meter is an instrument that displays the frequency of a periodic electrical signal various types of frequency meters are used. The frequency meter consists one inductive and one resistive coil.
It consists of a measuring transducer, which converts the quantity being measured into an alternating or direct current, and a measuring mechanism of an electrodynamic system figure 1. The vibratingreed frequency meter is one of the simplest devices. To the other terminal of the gate, a pulse of 1 sec is applied as shown in the fig. Electrodynamometer type wattmeter in general, a watt meter is used to measure the electric power of a circuit, or sometime it also measures the rate of energy transferred from one circuit to another circuit. Now let us look at constructional details of electrodynamometer. The wattmeter is electrodynamometer type, this instrument is highly reliable, and designed for use in laboratories or factories for precision measurement of power at ac and commercial frequencies 4565hz. Electrodynxmometer a reply cancel reply your email address will not be published.
Dynamometer type wattmeter working principle in these wattmeters, the field produced by the currentcarrying moving coil tries to come in line with the field produced by the currentcarrying fixed coil, and a deflecting torque is exerted on the moving system. We will discuss electrodynamometer type wattmeter working principle and its construction. Two movable coils are also used in the electrodynamometer meter. By properly designing the fixed current coil and moving coil pressure coil,dmdo can be made to vary linearly over a range of 40 50 on either side of the zero mutual inductance as shown in figure below. Outer limbs of the transformer have two windings, one on each limb. This type of instrument can be used either as an ammeter or as a voltmeter, but is generally used as a wattmeter. This is a online courseware website for sns college students through this website student can access their materials. Electrodynamometer definition of electrodynamometer by.
Operation principle of electrodynamometer type instrument. Two common types of frequency meters are the vibratingreed frequency meter and the movingdisk frequency meter. Electrodynamometer instruments are widely used as an ammeter, voltmeter and wattmeter. Vibrating reed type, electrical resonance type module. The traditional analog wattmeter is an electrodynamic instrument. In order to construct a circuit diagram we need two coils, three inductors. Electrodynamic instrument article about electrodynamic. Electrodynamic frequency meter working construction range. Changes in the frequency to be measured cause a change. An electrodynamo meter type wattmeter has two coils. Electrodynamometer type wattmeter electrical study app by saru tech. A dynamo meter type watt meter is used in various applications where the power or energy transfer has to be measured.
Thus, the power factor of the wattmeter becomes lagging, and. Pressure coil inductance the pressure coil of the electrodynamometer has some inductance. The part1 is connected in series with the l1 and c1 and likewise on the part2 side. This frequency meter also consists of two bridge rectifiers. 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. Ratiometer type frequency meter construction operation. The fixed coil is also called the current coil cc since it carries the load current or a fraction of it. The signal waveform whose frequency is to be measured is converted into tngger pulses and applied continuously to one terminal of an and gate. The following are the errors in the electrodynamometer wattmeter. Introduction to frequency meter universal counter need of frequency meter a digital frequency meter is a generalpurpose, basic, digital counter for measuring, setting, and monitoring frequencies, for counting random events, and for industrial counting applications. These frequency meters consist of two moving coils and a rectifier circuit. An instrument that measures electric current by indicating the level of magnetic attraction or repulsion between a fixed and a movable coil, one of which. The shape of scale of this instrument depends on the variation of dmdo i. For the love of physics walter lewin may 16, 2011 duration.
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