Wattmeters article about wattmeters by the free dictionary. Electrodynamometer wattmeter are often used for the measurement of power consumption. Wattmeters these instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Due to this the sizes of earlier wattmeter were large. The working principle of the electrodynamometer wattmeter is very simple and easy. Electrodynamometer type wattmeter construction and working. The average deflection torque of the coil is given as. Electrodynamometer wattmeter construction electrical concepts. Dynamometer type wattmeter construction and working principle.
In case of electrodynamometer wattmeter, i 1 is current through pc and i 2 is current through cc. For example, in using an electrodynamic wattmeter on direct current, two readings are taken, the direction of current flow through the instrument being reversed. 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. Dec 21, 2019 the working principle of the electrodynamometer wattmeter is very simple and easy. Construction and working principle advantages errors.
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. Power in an electric circuit is the product of voltage. The principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i. Meters, double element and three element dynamometer wattmeter, errors and compensations, measurement of unknown resistance, method of measuring low, measurement of inductance, ballistic. 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. Before we study the internal construction of electrodynamometer wattmeter, it very essential to know the principle of working of electrodynamometer type. Simultaneously, watt readings using a standard commercially available analogue wattmeter were also taken. Nov 29, 2014 the traditional form of wattmeter is called as dynamometer wattmeter. Electrodynamometer type wattmeter when a moving coil that is free to rotate is kept under the influence of a current carrying conductor, then automatically a mechanical force will be applied to the moving coil, and this force will make a little deflection of the moving coil. 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. The traditional form of wattmeter is called as dynamometer wattmeter. Jan 09, 2020 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 fieldit experiences a mechanical force and due to this mechanical force deflection of conductor takes place. The wattmeter is an instrument for measuring the electric power in watts of any given circuit. Study of ammeter, voltmeter and wattmeter connections.
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. The dynamometer wattmeter works on the motor principle. For example, in using an electrodynamic wattmeter on direct current, two readings are taken, the direction of. In electrodynamometer type wattmeter, moving coil works as pressure coil.
A wattmeter is a tool used to measure the amount of electricity being used. May 08, 2018 wattmeter, an instrument for the measurement of electric power, or the rate of supply of electric energy to any circuit. This type of watt meter consists of two types of coil, more specifically current coil and voltage coil. It uses for measuring the power of both the ac and dc circuits. Wattmeter1 free download as powerpoint presentation. Sep 30, 2019 the electrical measurements notes pdf em notes pdf book starts with the topics covering control and damping torques, design considerations type of p. Apr 26, 2019 electrodynamometer wattmeter are often used for the measurement of power consumption. What is the working principle of wattmeter and energy meter. 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.
The symmetrical resistive t network between the generator and load will provide v1 and v2 voltages proportional to, and in phase with, the load current and. A dynamometer type wattmeter reads 200w when its voltage coil is connected across the load whose voltage is 150 v. Sep 21, 2019 the working principle of the electrodynamometer wattmeter is very simple disturbs the main magnetic field of the electrodynamic wattmeter. It is similar in principle to the doublecoil dc ammeter or voltmeter in that it depends on the interaction of the fields of two sets of coils, one fixed and the other movable. The moving coil is suspended, or pivoted, so that it is free to rotate through a limited angle about an axis perpendicular to that of the fixed coils. The electrical measurements notes pdf em notes pdf book starts with the topics covering control and damping torques, design considerations type of p. The only safe choices to feed the non isolated wattmeter are batteries inside the isolated wattmeter housing mind the onoff switch a separate power supply trafo, rectifier, stabilizer fed from the mains supply, also inside the wattmeter housing mind the onoff switch. Nov 15, 2018 construction and working principle advantages errors. Scribd is the worlds largest social reading and publishing site. 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. Click here to download the pdf of this topic electrodynamometer type wattmeter. These instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters.
The term is generally applied to describe a particular form of electrodynamometer, consisting of a fixed coil of wire and an embracing or neighbouring coil of wire suspended so as to be movable. A modern digital wattmeter samples the voltage and current thousands of times a second. Subscribe to our mailing list and get interesting stuff and updates to your email inbox. A special meter movement designed especially for power measurement is called the dynamometer movement, and is similar to a darsonval or weston movement in that a lightweight coil of wire is attached to the pointer mechanism. 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. Pdf implementation of a digital wattmeter on fpga researchgate. Wattmeter, an instrument for the measurement of electric power, or the rate of supply of electric energy to any circuit. These coils are called the current coils of electrodynamometer type wattmeter. Pdf on oct 1, 2016, slami saadi and others published implementation of. 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 fieldit experiences a mechanical force and due this mechanical force deflection of conductor takes place. We know that instantaneous torque in electrodynamic type instruments is directly. Therefore this fixed coil is often called current coil or simply cc. The working principle of the electrodynamometer wattmeter is very simple disturbs the main magnetic field of the electrodynamic wattmeter. Wattmeter definition of wattmeter by the free dictionary.
Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power. The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. 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. Wattmeter article about wattmeter by the free dictionary. 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 fieldit experiences a mechanical force and due to this mechanical force deflection of conductor takes place. Design and hardware implementation of a digital wattmeter. Wattmeter theory and measurement of power 2 mcqs q1. The traditional analog wattmeter is an electrodynamic instrument. The matched triodes are operated in the nonlinear portion of their characteristic gridvoltage, platecurrent curves. Feb 20, 2018 in this video you will learn about how a wattmeter workand its construction.
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. In such a case, the leads of one wattmeter may have to be reversed in order to get a positive reading. Classification, absolute and secondary instruments, indicating instruments. The voltage across the pressure coil of the circuit is given as. A simplified electronic wattmeter circuit is shown in figure 3. Principle of electro dynamo meter type wattmeter free download.
Electrodynamometer type wattmeter electrical study app by saru tech. There is uniform scale is used in these types of instrument as moving coil moves linearly over a range of 40 degrees to 50 degrees on either sides. Jr is the large potential resistance, as free as possible from induct ance and. Now the reason is very obvious of using two fixed coils instead of one, so that it can be constructed to carry considerable amount of electric current. The current coils are connected in series with the circuit, while the potential coil is connected in parallel. These types of wattmeters operate on the same working principle on which the induction type ammeter and voltmeter operates. So the expression for the torque can be written as. Measurement of threephase power with the 2wattmeter method. Wattmeter design dc metering circuits electronics textbook. Refer to the schematic diagram in figure 41 for this description. They are generally classified by names descriptive of their operating principles. Wattmeter methods of measuring power expended upon. Measurement of threephase power with the 2wattmeter.
To understand the basic construction of a dynamometer instrument. A variety of wattmeters are available to measure the power in ac circuits. Download this big ebook and read the principle of electro dynamo meter type wattmeter ebook. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit.
The two coils are connected in different circuits for measurement of power. If two coils are connected such hence an electrodynamic instrument, when connected as shown in. May 20, 2020 these coils are called the current coils of electrodynamometer type wattmeter. The working principle elevtrodynamometer the electrodynamometer wattmeter is very simple and easy.
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