This page describes the basic working principle and construction of electrodynamometer wattmeter. Wattmeter is an electric instrument which is used to measure the electric power of various electric circuits. Jan 22, 20 the same principle applies to the induction energy meter, except that the movement is not limited by the spring but turns an aluminum disk constantly and racks up a counter mechanism. Sometimes it is not possible to have access of the neutral point in the star connection. Wattmeter working principle construction types of wattmeter. A dynamometer type wattmeter responds to the answer nakul pande. Dynamometer type wattmeter electrical technology youtube. It is recommended to read before going to understand the torque equation. This mechanical force deflects the pointer which is mounted on the calibrated scale.
This is a online courseware website for sns college students through this website student can access their materials. The three main types are electrodynamic, electronic and digital. Nov 29, 2014 the traditional form of wattmeter is called as dynamometer wattmeter. Measurement of threephase power with the 2wattmeter. Electronic wattmeter electronic wattmeters are used for direct, small power measurements or for power measurements at frequencies beyond the range of electrodynamometer type instruments. Wattmeter types diy electrical electronics projects. Calibration of electrodynamometer type instruments are highly affected by the changing the supply voltage frequency.
It may refresh several times per second or maybe once every 5 seconds depending on how sophisticated the monitoring circuit is. Measurement of threephase power with the 2wattmeter method. Dynamometer wattmeter working principle,construction. 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. The electrodynamic wattmeter, shown in figure 310, uses the reaction between the magnetic fields of two currentcarrying coils or sets of coils, one fixed and the other movable. An electrodynamometer is an instrument used for measuring the electric power. Here, the current flows through the current coil from the source to the load. So far as i know there are only single phase and three segment connection. But in these instruments, the operating field is produced by the fixed coil instead of a permanent magnet. Electrodynamometer introduction it have nonuniform scale it is sensitive to overloads and any mechanical impacts. Electrodynamometer by muhammad nur zakwan zainal on prezi. A dynamometer type wattmeter is most commonly employed for measurement of power in a.
All articles of this app are totally based on practical experiences as well as a strong base of theoretical knowledge and is written in very simple and. 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. The two coils are connected in different circuits for measurement of power. Electrodynamometer instruments or electrodynamic instruments have fixed coil divided into two sections and a moving coil. However, there is one difficulty in this type of connection. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit.
Dynamometer type wattmeter works on very simple principle and this principle can be stated as when any electric current carrying conductor is placed inside a magnetic field, it experiences a mechanical force and due this mechanical force deflection of conductor takes place. 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. Power factor meters electrodynamometer type power factor. However, it differs from induction ammeter or voltmeter in so far that separate two coils are used to produced the rotating flux in place of one coil with phase split arrangement. Electrostatic type wattmeter is useful in measuring very small powers in dielectric circuits. Dynamometer wattmeter electrical engineering assignment. The average of the instantaneous voltage multiplied by the current is the true power. A simplified electronic wattmeter circuit is shown in figure 3. Single phase induction meters are very popular for domestic and industrial use because of its wide application as energy meter. Simultaneously, watt readings using a standard commercially available analogue wattmeter were also taken.
Given the two wattmeter readings from the twowattmeter method used on a threephase balanced load, it is possible to find the tangent of the phase impedance angle as times the ratio of the difference between the two wattmeter readings and their sum, based on equation 4. This device is available in a purely electronic form too which is known as digital wattmeter. They are quite costly as compared to other instruments. So, it works for all operating systems including mac, windows, and linux. It may refresh several times per second or maybe once every 5 seconds. The fixed coils are made up of a few turns of a comparatively large conductor. The wattmeter is used to tune the stations antenna and to determine if the antenna and transmitter are working properly by allowing the measurement of the systems forward and reflected power. Before we study the internal construction of electrodynamometer type wattmeter, it is essential to know the working principle of electrodynamometer type wattmeter. This is one of the advantages of this type ofmeter.
Apr 19, 2018 for the love of physics walter lewin may 16, 2011 duration. It is important to avoid excessive current flow in the voltage and current coils of a wattmeter. Working forces are small as compared to moving iron type instruments. It is based on the principle that mechanical force exists between two current carrying conductors. Electronic wattmeter a modern digital electronic wattmeterenergy meter samples the voltage and current thousands of times a second. The principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i.
Given the two wattmeter readings from the two wattmeter method used on a threephase balanced load, it is possible to find the tangent of the phase impedance angle as times the ratio of the difference between the two wattmeter readings and their sum, based on equation 4. It consists of a pair of fixed coils, known as current coils, and a movable coil known as the potential coil. Choose from a variety of file types multiple pdf files, microsoft word documents, microsoft excel spreadsheets, microsoft powerpoint. Electronic wattmeter a modern digital electronic wattmeter energy meter samples the voltage and current thousands of times a second.
For the love of physics walter lewin may 16, 2011 duration. When using the twowattmeter method, it is important to note that the reading of one wattmeter should be reversed if the power factor of the system is less than 0. Wattmeters these instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Apr 08, 2018 the shape of scale of this instrument depends on the variation of dmdo i. The wattmeter is an instrument for measuring the electric power in watts of any given circuit. The movement of the needle is the result of a vector product between the magnetic fields of two coils, one carries the voltage and one carries the load current, producing a torque. If two coils are connected such that, current proportional to the load voltage, flows through one coil and current proportional to the load current, flows through another coil, the meter can be calibrated directly in watts. Electronic wattmeter electronic wattmeters are used for direct, small power measurements or for power measurements at frequencies beyond the range of electrodynamometertype instruments. As the deflecting torque is very small it is not a commercial wattmeter. The shape of scale of this instrument depends on the variation of dmdo i.
Power factor meter working principle the basic working principle of power factor meter is similar to that of dynamometer type wattmeter i. The same principle applies to the induction energy meter, except that the movement is not limited by the spring but turns an aluminum disk constantly and racks up a counter mechanism. Dynamometer type wattmeter and its deflecting torque. Principle of operation of the electrodynamic wattmeter. The wattimeter has a rotating conductive disk which is crossing two magnetic flux, one is produced by coil connected to ac supply voltage and the other by a coil connected to ac current, as they are ac some eddy or foucault currents are produced. The dynamometer wattmeter works on the motor principle. Top answer the movement of the needle is the result of a vector product between the magnetic fields of two coils, one carries the. If the coils are connected so that a value of current proportional to the load voltage flows in one, and a value of current proportional to the load current. Their working depends on the theory that the current carrying conductor placed in a magnetic field experiences a mechanical force. When using the two wattmeter method, it is important to note that the reading of one wattmeter should be reversed if the power factor of the system is less than 0. Nov 30, 2015 an electrodynamometer type watt meter has two coils. How to combine files into a pdf adobe acrobat dc tutorials. As shown in the above figure, the wattmeter has two sets of coils. The traditional form of wattmeter is called as dynamometer wattmeter.
In such a case, the leads of one wattmeter may have to be reversed in order to get a positive reading. Disadvantages of electrodynamic type power factor meters. The current coil having low resistance is connected in series with the load so that it carries the load current. The scale of the wattmeter illustrated in figure 2 is read directly only when the range switches are set to 1 a and 120 v. This app covers entire aspects of the subject, from basic engineering to advanced and modern topics related to electrical engineering and technology. 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.
Three wattmeter method power measurement in an ac circuit is measured with the help of a wattmeter. Aa magnet is used to brake the spinning of the disk through foucault induced currents, otherwise, it would speed up out of control. What is the working principle of wattmeter and energy meter. May 15, 2018 disadvantages of electrodynamic type power factor meters. Electrodynamometer type wattmeter construction and working. 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. Induction meter includes types such as induction voltmeters, induction ammeters and induction watthour meters. Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power. A repulsive force exists on a plate placed in an electric field. The fixed coil is also called the current coil cc since it carries the load current or a fraction of it. A dynamo meter type watt meter is used in various applications where the power or energy transfer has to be measured. Design and hardware implementation of a digital wattmeter.
Like in the one wattmeter methord, where the wattmeter is connected in one phase, in the three wattmeter method, it is connected in all 3phases. Apr 24, 2018 torque equation in electrodynamometer instruments. A wattmeter does a complex job, measuring the power flowing through an electrical circuit. We generally provide spring control with pneumatic damping in a dynamometer type wattmeter. The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. 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.
What is the difference between an energy meter and wattmeter. Feb 20, 2018 in this video you will learn about how a wattmeter workand its construction. Now let us look at constructional details of electrodynamometer type wattmeter. Megger working principle types history uses of megger. The electrodynamic wattmeter, shown in figure 310, uses the reaction between the magnetic fields of two currentcarrying coils. If you are already aware of constructional feature then you may proceed. It simultaneously measures the voltage and current values and multiplies them to give power in watts. Electrodynamometer type wattmeter electrical study app by. Electric power is measured by means of a wattmeter.
Dynamometer type wattmeter construction and working. Dynamometer type wattmeter working your electrical guide. An electrodynamometer type watt meter has two coils. Construction and working principle of electrodynamometer type wattmeter. A wattmeter is an instrument which consists of two coils called current coil and potential coil. We have used several lamps having watt ratings of 40, 60 and 100watt as loads and measured real power dissipated at those loads using our designed digital wattmeter. The basic principle was laid out in an 1848 paper by wilhelm weber 18041891. Therefore, a power measurement in a dc circuit can be generally carried out using a voltmeter v and an ammeter a according to one of the arrangements shown in figure 39. If you have a basic watt meter, the display gives the instantaneous power used at that time. The true power divided by the apparent voltamperes va is the power factor. Dynamometer type wattmeter construction and working principle. 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. The electrodynamometer wattmeter has two types of coils.
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