The next method we are going to discuss is the one wattmeter method. Measurement of threephase power with the 2wattmeter. Single phase energy meter working of single phase induction. It uses for measuring the power of both the ac and dc circuits. Induction type of energy meters are universally used for measurement of energy in domestic and industrial a.
These coils are called the current coils of electrodynamometer type wattmeter. The torque produces with the reaction of rotating magnetic field and eddy current. Construction of dynamometer type wattmeter, dynamometer type wattmeter working. Also they are inexpensive and accurate, and retain their accuracy over a wide range of loads and temperature conditions. 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. Refer to the schematic diagram in figure 41 for this description. Given below is the picture of single phase induction type meter. Dynamometer type wattmeter electrical technology duration. Induction type meters electromagnetic induction inductor scribd. The traditional form of wattmeter is called as dynamometer wattmeter. Dynamometer type wattmeter working your electrical guide. As shown in the above figure, the wattmeter has two sets of coils. The following figure shows the dynamometer wattmeter for measuring the power. Dynamometer type wattmeter electrical technology zfgs33adsa8.
Induction type energy meter ii electrical technology ii unit 3. Dynamometer type wattmeter electrical technology youtube. Study of single phase induction type energy meter or watt. With some little modifications, it can be used as a wattmeter for the power measurements. This type of wattmeter works on the principle of torque production by induced currents in a short circuited secondary circuit. Working of single phase induction type energy meter. Basically, the induction energy meter may be derived from the induction watt meter by substituting for the spring control and pointer an eddy current brake and a. 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. Cycloconverter fed to induction motor cycloconverter fed to induction motor cyclo converter is a single stage frequency conversion device which converts fixed ac freque.
Overview of single phase induction type energy meter. Wattmeter types diy electrical electronics projects. 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. These wattmeters consists of two laminated electro magnets and one of them is excited by the current with exciting winding. Measurements and instrumentation questions and answers. The current coil of the wattmeter is connected to one phase, and the pressure coil is connected to the other phase of the line. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit. Is induction wattmeter,energy meter and watt hour meter the same thing. These instruments are used on both ac and dc supplies.
Basically, the induction energy meter may be derived from the induction wattmeter by substituting for the spring control and pointer an eddy current brake and a. The two fixed coils are aircored to avoid hysteresis effects when used on ac. Dynamometer type wattmeter electrical technology induction type energy meter ii electrical technology ii. Induction type wattmeter, watthour meter, dynamometer type power factor meter. The basic working of single phase induction type energy meter is only focused on two mechanisms. Reactive power measurement in balanced threephase circuit the single wattmeter method is used for measuring the power of the balanced threephase circuit. Earlier these fixed coils are designed to carry the current of about 100 amperes but now the modern wattmeter are designed to carry current of about 20 amperes in order to save power. In a household single phase induction type wattmeter, the meter can be reversed by. Electrostatic type wattmeter for small amount of a. There are four main parts of the operating mechanism i driving system ii moving system iii braking system. Induction type energy meter ii electrical technology ii unit 3 duration. Why does induction type wattmeter cant be used for dc. 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.
Electrodynamometer type, induction type, single phase and three phase wattmeter, compensation, energymeters. Single phase induction type energy meter consists of four important systems which are written as follows. Dynamometer type wattmeter construction and working. 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.
Meters, double element and three element dynamometer wattmeter, errors and compensations, measurement of unknown resistance, method of measuring low, measurement of inductance, ballistic. Wattmeter working principle construction types of wattmeter. Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power. It has a few decisive advantages like sturdy construction and very long circular scale around 300. 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 directional power relay construction. The dynamometer wattmeter works on the motor principle. Vibrating reed type, electrical resonance type moduleii 10 hours. During this test, the motor is operated at rated voltage and frequency and normally loaded mechanically by brake and pulley arrangement. Electronic the traditional analog wattmeter is an electrodynamic instrument. Electrodynamometer type instruments your electrical home.
Power factormeter synchroscope frequency meter digital. Dynamometer and induction type energy meterinduction typeinstrument transformers. 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. Mechanism of rotation of an aluminum disc which is made to rotate at a speed proportional to the power. Power factormeter synchroscope frequency meterdigital. Instrumentation and process control pdf book agrimoon. In the induction type single phase energy meter, the flux produced by shunt magnet pressure or voltage coil current. Electrical measurements pdf notes em pdf notes smartzworld. The instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the electrodynamo meter wattmeter.
Wattmeter working principle construction types of wattmeter dynamometer type wattmeter induction wattmeter working principle uses of wattmeter. Mechanism of counting and displaying the amount of energy transferred. The current coils connected in series with the circuit, while the potential coil is connected in paralell. When a disc or drum of a nonmagnetic conducting material is placed i. A dynamometer type wattmeter primarily consists of two coils called fixed coil and moving coil. So an induction wattmeter can work on ac circuits only. Electrodynamometer type wattmeter construction and working. In a household single phase induction type wattmeter, the. To measure power it is not necessary to use three wattmeter, even two wattmeters can be used for the purpose. 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. Measurement of three phase power wattmeter methods. Thus this type of relay is essentially a wattmeter and the direction of the torque set up in the relay depends upon the direction of the current relative to the voltage, with which it is associated.
In analog voltmeters, the pointer moves over a calibrated scale in proportion to potential difference across the points where as in case of digital voltmeters, it displays numerical values with the help of. Routine test of three phase induction motor vishant naik1, saurabh k singh2, sahil chawhan3. This device is available in a purely electronic form too which is known as digital wattmeter. The spindle of this disc carries a moving contact which bridges two fixed contacts when the disc rotates through an angle, which is adjustable between 0 o to 360 o. The reaction between the rotating flux and the eddy current produced by it creates a. The load test on induction motor is performed to compute its complete performance i. When a disc or drum of a nonmagnetic conducting material is placed in a rotating magnetic field, eddy currents are induced in disc or drum. This app covers entire aspects of the subject, from basic engineering to advanced and modern topics related to electrical engineering and technology. Themostobviousnullmethodconsistsinusingavariableinductance inthepotentialcircuit. A wattmeter, measures electric power of the given an electric apparatus or circuit. Driving system consists of two electromagnets on which pressure coil and current coils are wounded, as shown above in the diagram. The controlling torque is provided by spiral springs. Induction type energy meter ii electrical technology ii. A wattmeter is used to measure the voltage in an electronic circuit.
Induction type of meters possesses lower friction and higher torqueweight ratio. Dynamometer and induction type energy meterinduction type instrument transformers. Yes, its right induction type wattmeter cannot work for dc power measurement. The electrodynamometer type instruments are often used in accurate a. Wiring materials and accessories rating of wiring materials, types of wiring.
But in these instruments, the operating field is produced by the fixed coil instead of a permanent magnet. Constructional details and operation of non directional over current relay wattmeter type it has a metallic disc free to rotate between the poles of two electromagnets em. Meter give the average power consumed over a period of time while the watt meter gives the instantaneous power. These wattmeters provide accurate readings only when frequency and supply voltages are constant. The device consists of a pair of fixed coils, known as current coils, and a movable coil known as the potential coil. Induction type siqgle phase and three phase energy meter, compensation, creep, error, testing, frequency meters. When a drum or disc of a non magnetic conducting material is placed in a rotating magnetic field, eddycurrents are induced in it. It gives the same angle deflection for a given power. A wattmeter is suitable for power measurement in dc as well ac systems.
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