Unitiv single phase induction type energy meter driving and braking torques, errors and compensation. Working of single phase induction type energy meter the basic working of single phase induction type energy meter is only focused on two. The basic dynamometer type wattmeter working principle is that when a current carrying moving coil is placed in the magnetic field produced by the current carrying fixed coil, a force is exerted on the coil sides of the moving coil and deflection takes place as shown in figurea. Sometimes it is not possible to have access of the neutral point in the star connection. Measurements and instrumentation objective type questions. Refer to the schematic diagram in figure 41 for this description. Ac watt meter project 20140908 danger only for the non mains isolated versions important warning. The two coils are connected in different circuits for measurement of power. A wattmeter is used to measure the voltage in an electronic circuit. However, it differs from induction ammeter or voltmeter in so. The ammeter and voltmeter are both vulnerable to overheating in case of an overload, their pointers will be driven off scale but in the wattmeter, either or even both the current and potential circuits can overheat without the pointer approaching the end of the scale. Originally only a tool of professionals there are now many different types of the device available that are both cheap and easy to use and available for home use.
Electrodynamometer type, induction type, single phase and three phase wattmeter, compensation, energymeters. It is widely use to measure the energy in domestic as well as in industry. Study of active electric energy meters behavior of induction and electronic types. This device is available in a purely electronic form too which is known as digital wattmeter. Why does induction type wattmeter cant be used for dc. 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. Wattmeter types diy electrical electronics projects. As shown in the above figure, the wattmeter has two sets of coils. Induction type wattmeter requirement of phase difference. An 8 bit converter type ad converter makes at least 8000conversionssec. Type k induction integrating wattmeter by fort wayne ind. 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.
Be semesteriii electrical question bank electrical and. If you dont see any interesting for you, use our search form on bottom v. A wattmeter is an instrument which consists of two coils. Induction type energy meter essentially consists of following components. Now let us look at constructional details of electrodynamometer type wattmeter. Therefore, this type of meter is also called an integrating meter. Meter with lag adjustment devices low power factor wattmeter. To study the construction and working of single phase energy meter and to find. Induction type single phase energy meters measure electric energy in kwh var none of the above c 17. A wattmeter is generally used for checking on the power supply of.
The movable coil carries a needle which moves over a. It has a few decisive advantages like sturdy construction and very long circular scale around 300. Pdf study of active electric energy meters behavior of induction. For obtaining the required phase difference published on 10 nov 15. 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 operating principle of the induction type instrument is based on the two pole.
The controlling torque is provided by spiral springs. Elevation, side view and plan of the object given below. 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. In induction type wattmeter both current and pressure coils are required. Induction type wattmeter, watthour meter, and dynamometer type power factor. 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. The two coils are connected in different circuits for measurement of.
The ammeter and voltmeter are both vulnerable to overheating in case of an overload, their pointers will be driven off scale but in. In case of low voltage circuits three potential coils may. In all induction meter two fluxes are produce by two different alternating currents on its metallic disc. Download the book into available format new update. Study of single phase induction type energy meter or watt. A wattmeter, measures electric power of the given an electric apparatus or circuit. Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power. Induction type siqgle phase and three phase energy meter. Im considering that the question intends to understand about why a watt meterone of two shows a negative reading with induction motor on noload using two watt meter method. Electrostatic type wattmeter for small amount of a. Driving system consists of two electromagnets on which pressure coil and current coils are wounded, as shown above in the diagram. When a drum or disc of a non magnetic conducting material is placed in a rotating magnetic field, eddycurrents are induced in it. Dec 07, 2015 on this page you can read or download advantages disadvantages of electrodynamic wattmeter in pdf format. The reaction between the rotating flux and the eddy current produced by it creates a torque which rotates the disc or drum.
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. A movingcoil permanentmagnet instrument can be used as fluxmeter. Single phase induction type energy meter consists of four important systems which are written as follows. Single phase energy meter working of single phase induction. The principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i. Single phase induction type energy meter pdf to understand the basic construction and different components of a single phase induction type energy meter. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit.
Which is known as the general expression for the deflecting torque in the induction type meters. If you cannot read the numbers in the above image, reload the page to generate a new one. Here we are going to discuss about the single phase induction type in detail. A dynamo meter type watt meter is used in various applications where the power or energy transfer has to be measured. Im considering that the question intends to understand about why a wattmeterone of two shows a negative reading with induction motor on noload using twowattmeter method. The wattmeter is an instrument for measuring the electric power in watts of any given circuit. Dynamometer type wattmeter working your electrical guide. Measurement of power 150910 usaid sarienergy integration. Jun 03, 2017 yes, its right induction type wattmeter cannot work for dc power measurement. Induction type meters electromagnetic induction inductor scribd. Why does the wattmeter show a negative reading during the no. Wattmeters these instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Conference paper pdf available september 2006 with 238 reads.
The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. Originally only a tool of professionals there are now many different types of the device available that are both cheap. A wattmeter is an instrument which consists of two coils called current coil and potential coil. This article is only focused about its constructional features and its working. Jul 25, 2018 which is known as the general expression for the deflecting torque in the induction type meters. Nov 30, 2014 this type of wattmeter works on the principle of torque production by induced currents in a short circuited secondary circuit. Given below is the picture of single phase induction type meter.
Measurement of threephase power with the 2wattmeter. Measurement of power in 3 phase circuits 3wattmeter method the method is applicable in 3phase 4 wire circuits, works well for balanced and unbalanced loads. This type of wattmeter works on the principle of torque production by induced currents in a short circuited secondary circuit. Mechanism of rotation of an aluminium disc which is made to rotate at a speed proportional to the. What links here related changes upload file special pages permanent. The movable coil carries a needle which moves over a suitable marked scale. The two circuits of a wattmeter can be damaged by excessive current. The dynamometer wattmeter works on the motor principle. On this page you can read or download advantages disadvantages of electrodynamic wattmeter in pdf format.
Induction type wattmeter a thin aluminium disc mounted on the spindle is placed in between the two magnets so that it cuts the fluxes of both the magnets. Induction type single phase energy meters measure electric energy in. Three wattmeter method power measurement in an ac circuit is measured with the help of a wattmeter. However, there is one difficulty in this type of connection. You should also make a dc measurement of stator winding linetoline resistance. Electromagnetic wattmeters are used for measurement of utility frequency. Record all nameplate information for the induction motor. All electrical parts of the meter are connected to the live mains supply. The traditional form of wattmeter is called as dynamometer wattmeter. Because for dc supply current coil is short and produced flux is very very small then flux linkage with pressure coil is very very small then needle will remains at zer. Costeffective and flexible singlephase energy meter. Single phase induction type energy meters is very commonly used to. The current coil having low resistance is connected in series with the load so that it carries the load current.
Why is dynamometer type instrument chiefly used as a wattmeter. An induction type single phase energy meter, as show in fig. Advantages disadvantages of electrodynamic wattmeter. In two wattmeter method the current coils of the wattmeter are connected with any two lines, say r and y and the potential coil of each wattmeter is joined on the. Dynamometer type wattmeter construction and working.
Construction and working principle of electrodynamometer type wattmeter. So an induction wattmeter can work on ac circuits only. Spiral coil springs hold the needle to a zero position. Study the construction and working of single phase energy. Electrodynamometer type wattmeter construction and working. In 3phase 3 wire circuits an artificial neutral is created through 3 equal high resistances connected in star. Single phase induction meters are a popular type of meters, because of its wide application as energy meter or watthour meter. The resistance in the circuit of the moving coil of a dynamometer wattmeter should be. One singlephase wattmeter plus miscellaneous apparatus as needed. 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. Nov 29, 2014 the traditional form of wattmeter is called as dynamometer wattmeter. The basic working of single phase induction type energy meter is only focused on two mechanisms.
Jul, 2016 the principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i. The induction type voltmeter operates on the either shaded pole method or on. Overview of single phase induction type energy meter. Working of single phase induction type energy meter the basic working of single phase induction type energy meter is only focused on two mechanisms. Questions and answers list eie south central railway. Hence it is the working of induction type energy meter, adjustment of induction type energy meter. 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. The induction type wattmeter is very simple as construction wise. Mechanism of rotation of an aluminum disc which is made to rotate at a speed proportional to the power. Two wattmeter method of power measurement two wattmeter method can be employed to measure the power in a 3 phase, three wire star or delta connected the balanced or unbalanced load.
The following figure shows the dynamometer wattmeter for measuring the power. It consist of a pair of fixed coils, known as current coils and movable coil known as the potential coil. Jul 17, 2016 principle of induction type instruments. 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. Because for dc supply current coil is short and produced flux is very very small then flux linkage with pressure. Measurement of threephase power with the 2wattmeter method. Yes, its right induction type wattmeter cannot work for dc power measurement. Now there are two types of induction meters and they are written as follows.