Electrodynamometer type, induction type, single phase and three phase wattmeter, compensation, energymeters. In all induction meters we have two fluxes which are produced by two different alternating currents on a metallic disc. Measuring instruments inductor measuring instrument scribd. Now we will explain the measurement threephase power measurement using three wattmeter method. Jul 25, 2018 induction type meters july 25, 2018 february 24, 2012 by electrical4u the principle of working and construction of induction type meter is very simple and easy to understand thats why these are widely used in measuring energy in domestic as well as industrial world. For obtaining the required phase difference published on 10 nov 15.
Energy meters are almost inherently free from errors due to. 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. In all induction meters we have two fluxes which are produced by two different alternating currents on. It has a few decisive advantages like sturdy construction and very long circular scale around 300. An induction watthour meter is essentially an induction wattmeter with control spring and pointer removed but brake magnet and counting mechanism provided. It works on the principle that the iron place near the magnet attracts towards it. Induction wattmeters electrical engineering assignment.
So an induction wattmeter can work on ac circuits only. This type of wattmeter works on the principle of torque production by induced currents in a short circuited secondary circuit. 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. Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power. The fixed coils, therefore, form the current coil or simply c. Wattmeter types diy electrical electronics projects.
It has two laminated electromagnets one is excited by the current in the main circuitits exciting winding being joined in series with the circuit, hence it is also called series magnet. 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. The pressure coil circuit of induction type instrument is made as inductive as. Hence it is the working of induction type energy meter, adjustment of induction type energy meter. The resolution bandwidth filter or rbw filter is the bandpass filter in the if path. Enter your email below to receive free informative articles on electrical.
Instrumentation and process control pdf book agrimoon. A rotating magnetic field is produced by the coils of the instrument. To find out g o and b o the induction motor is made to run at synchronous speed by using another machine. Dynamometer type wattmeter electrical technology youtube. Electrodynamometer type wattmeter construction and working. The power in threephase circuits is measured by threephase wattmeters, which are based on the structural joining of three or two singlephase wattmeters. 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. Wattmeter an instrument for measuring the power of an electrical current in watts. Measurement of threephase power with the 2wattmeter method. The additional machine helps to supply the friction and windage losses, under this conditions, the slip s0 and the current drawn by the induction motor is i o only since s0, the term r l r 2 1s1 becomes the load resistance r l 0.
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. Before we study the internal construction of electrodynamometer type wattmeter, it is essential to know the working principle of electrodynamometer type wattmeter. No load test and locked rotor test in an induction motor. Electrostatic type wattmeter for small amount of a.
Induction type instruments, working principle of induction. 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. Jul, 2016 the principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i. The true power divided by the apparent voltamperes va is the power factor. Wattmeter working principle construction types of wattmeter. Measurement of three phase power wattmeter methods. Nov 29, 2014 the traditional form of wattmeter is called as dynamometer wattmeter. However, it differs from induction ammeter or voltmeter in so far that separate two coils are used to produced the rotating flux in. The magnetic field induces by the electromagnet whose strength depends. 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. Dynamometer type wattmeter electrical technology study buddy. Induction type of voltmeter and ammeter free download as powerpoint presentation.
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. Jul 17, 2016 principle of induction type instruments. Induction type siqgle phase and three phase energy meter, compensation, creep, error, testing, frequency meters. Meters, double element and three element dynamometer wattmeter, errors and compensations, measurement of unknown resistance, method of measuring low, measurement of inductance, ballistic. A variety of wattmeters are available to measure the power in ac circuits. 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.
Dynamometer type wattmeter induction type wattmeter. Usually current coil is fixed and pressure coil is free to move. Measurement of threephase power with the 2wattmeter. Why does induction type wattmeter cant be used for dc. Publication date 1900 topics electric meters collection. Matrix algebra is one of the powerful tools to handle practical problems arising in the field of engineering. The fixed coils or field coils arc connected in series with the load and so carry the current in the circuit. In power plants the power is measured by panel static wattmeters, which are usually ferrodynamic and, less frequently, of the induction type. Adjusting the bandwidth of this filter allows for the discrimination of signals with closely spaced frequency components, while also changing the measured noise floor. Measurements and instrumentation questions and answers pdf 26.
Wattmeter article about wattmeter by the free dictionary. Electrodynamometer type, induction type, single phase and three. 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. A moving iron ammeter may be compensated for frequency errors by a.
One singlephase wattmeter plus miscellaneous apparatus as needed. Due to alternating fluxes there is an induced emf, the emf produced at one. Single phase induction type energy meter construction,working principle,operation,creeping,torque equation the measurement of energy is the same process as measurement of power except that the instrument not merely indicates the power or rate of supply of energy but must take into account also the length of time for which the rate of energy is. The following figure shows the dynamometer wattmeter for measuring the power. When a drum or disc of a non magnetic conducting material is placed in a rotating magnetic field, eddycurrents are induced in it. Mechanism of rotation of an aluminum disc which is made to rotate at a speed proportional to the power. Record all nameplate information for the induction motor. Measurements and instrumentation 2 mark questions answers pdf. Induction type wattmeter requirement of phase difference.
Single phase induction meters are very popular for domestic and industrial use because of its wide application as energy meter. Wattmeters article about wattmeters by the free dictionary. Electronic wattmeter a modern digital electronic wattmeterenergy meter samples the voltage and current thousands of times a second. 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. Jun 03, 2017 yes, its right induction type wattmeter cannot work for dc power measurement. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit. The torque produces with the reaction of rotating magnetic field and eddy current. The instrument in which the moving iron is used for measuring the flow of current or voltage is known as the moving iron instrument. Feb 15, 2019 single phase induction type energy meter. An induction type single phase energy meter, as show in fig has following main parts of the. The reaction between the rotating flux and the eddy current produced by it creates a. Overview of single phase induction type energy meter. 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.
The dynamometer wattmeter works on the motor principle. The traditional analog wattmeter is an electrodynamic instrument. Measurements and instruments viva short questions and. The average of the instantaneous voltage multiplied by the current is the true power. The fig shows how an induction disc type over current relay with split pole i. You should also make a dc measurement of stator winding linetoline resistance. Three wattmeter method is used to measure power in 3 phase, 4wire circuits. Mar 18, 2017 single phase induction meters are very popular for domestic and industrial use because of its wide application as energy meter. Wattmeter working principle construction types of wattmeter dynamometer type wattmeter induction wattmeter working principle uses of wattmeter. Single and three phase circuits up to 1600 volt blocking, s inside scrdiode circuit with free wheeling diode three phase diode bridge b2t. Working of single phase induction type energy meter. The principle of working and construction of induction type meter is very simple and easy to understand thats why these are widely used in measuring energy in domestic as well as industrial world. Sep 05, 2012 induction type instruments the principle of operation of induction instrument is similar to that of induction motor.
The basic working of single phase induction type energy meter is only focused on two mechanisms. Measuring instruments free download as powerpoint presentation. Electrodynamometer type wattmeter 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. The two coils are connected in different circuits for measurement of power. Induction meter includes types such as induction voltmeters, induction ammeters and induction watthour meters. The electrical measurements notes pdf em notes pdf book starts with the topics covering control and damping torques, design considerations type of p. Wattmeter gives direct indication of average power in the circuit.
Dynamometer and induction type energy meterinduction typeinstrument transformers. Trms three and single phase digital wattmeters more than a wattmeter, a power, optical lead. A wattmeter is used to measure the voltage in an electronic circuit. The above figure shows the wattmeter type induction relay. Yes, its right induction type wattmeter cannot work for dc power measurement. 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.
If you cannot read the numbers in the above image, reload the page to generate a new one. Also, on analog wattmeters, the potential coil carries a needle that moves over a scale to indicate. The reaction between the rotating flux and the eddy current produced by it creates a torque which rotates the disc or drum. Vibrating reed type, electrical resonance type moduleii 10 hours. Type k induction integrating wattmeter by fort wayne ind. Study of single phase induction type energy meter or watt. Dynamometer type wattmeter construction and working principle. As shown in the above figure, the wattmeter has two sets of coils. The traditional form of wattmeter is called as dynamometer wattmeter. Engineering mathematics 2 ma8251 notes pdf free download. When a three phase induction motor connected to a single phase power supply using the steinmetz connection operates in a practical noload condition, not all windings consume active power.
This device is available in a purely electronic form too which is known as digital wattmeter. Induction type indicating instruments lesson 10 essentials of indicating instruments 4649 lesson 11 principle of induction type instruments 5053 lesson 12 induction type voltmeter and ammeter 5456 lesson induction type wattmeter, watthour meter, dynamometer type power factor meter 5761 module 5. 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. Ma8251 notes engineering mathematics 2 regulation 2017. The principle of working and construction of induction type meter is very simple and. The most common wattmeters are the dynamometer type, in which the mechanism consists of an immovable coil connected in series to a load the current circuit and. Measurement is an act or the result of comparison between the quantity and a predefined standard. Induction type wattmeter, watthour meter, and dynamometer type power factor. The force of attraction depends on the strength of the magnet field. Directional over current relay linkedin slideshare. Dynamometer type, induction type, electrostatic type, suspendedcoil torsion, pivotedcoil.
Ma8251 notes engineering mathematics 2 regulation 2017 anna university free download. Dynamometer type wattmeter construction and working. Jan 27, 2018 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. Induction type energy meter ii electrical technology ii unit 3 s. Mechanism of counting and displaying the amount of energy transferred. Induction type wattmeter, watthour meter, dynamometer type power factor meter. They are generally classified by names descriptive of their operating principles. In induction type wattmeter both current and pressure coils are required. The principle of operation of an induction wattmeter is same as that of induction ammeters and voltmeters i. The coil is pivoted on the jewelled bearing and thus the coil is free to rotate. Nov 30, 2014 this type of wattmeter works on the principle of torque production by induced currents in a short circuited secondary circuit. The other electromagnet is excited by current which is proportional to the voltage of the circuit. Electronic wattmeter a modern digital electronic wattmeter energy meter samples the voltage and current thousands of times a second. A wattmeter, measures electric power of the given an electric apparatus or circuit.
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