What are the applications of Electrodynamometer type instrument?
What are the applications of Electrodynamometer type instrument?
Electrodynamometer type instruments are used as a.c voltmeters and ammeters both in the range of power frequencies and lower part of the audio frequency range. They are used as watt-meters,varmeters and with some modification as power factor meters and frequency meters.
What is Electrodynamometer instrument?
An electrodynamometer or simply Dynamometer wattmeter is an instrument that is universally used for the measurement of DC as well as AC electric power. It works on the principle of dynamometer i.e. a mechanical force acts between two current carrying conductors.
What is Electrodynamometer movement?
The electrodynamometer movement meter has the same basic operating principle as the D’Arsonval meter movement, except that the permanent magnet is replaced by fixed coils. The moving coil and pointer, which are attached to the coil, are suspended between and connected in series with the two field coils.
What is the difference between MI and MC type instruments?
The MI iron instrument has the non-uniform scale. The moving iron instrument consumes more power as compared to the moving coil instrument. The moving iron instrument is used for measuring both the direct and alternating current whereas the moving coil is used for the DC measurement.
Why Electrodynamometer instruments are known as transfer instruments?
These instruments have the same accuracy for both dc and ac. Explanation: Precision type electrodynamometer (EMMC) is used in the standardization process of the potentiometer and hence It is a transfer instrument.
Which damping is used in Electrodynamometer?
Air friction damping
Air friction damping is used, as eddy current damping will distort the weak operating magnetic field and thus it may leads to error. There is uniform scale which is used in these types of instrument as moving coil moves linearly over a range of 40 degrees to 50 degrees on either side.
What is the working principle of Electrodynamometer?
The Electrodynamometer wattmeter working principle is very simple and easy. It is based on the theory of a current-carrying conductor experiences a magnetic force when it is placed in a magnetic field. The moving coil carries the current directly proportional to the voltage and connected across the voltage.
What are the advantages of Electrodynamometer?
1)As the instrument coils are air cared, so these instruments are free from hysteresis and eddy current errors. 2)These instruments can be used on both a.c. and d.c. and since they have a precision grade accuracy, they are very useful as transfer instruments.
What type of control is used for Electrodynamometer type wattmeter?
The gravity control and the spring control are the two types of control system. Out of two, the Electrodynamometer Wattmeter uses spring control system.
What are the disadvantages of MI type instrument vs PMMC type instrument?
These instruments suffer from error due to hysteresis, frequency change and stray losses. The scale of moving iron instrument is not uniform like PMMC instrument.
How Electrodynamometer is used as ammeter and voltmeter?
The EDM movement is extensively used to measure power, both dc and ac, for any waveform of voltage and current. An EDM used as a voltmeter or ammeter has the fixed coils and movable coil connected in series, thereby reacting to I2.
What are the applications of electrodynamometer?
Electrodynamometer instruments are capable of serving as transfer instruments. Indeed, their principal use as ammeters and voltmeters in laboratory and measurement work and as standards for calibration of other instruments as their accuracy is very high.
What are the constructional details of electrodynamometer type wattmeter?
Now let us look at constructional details of Electrodynamometer Type Wattmeter. It consists of following parts There are two types of coils present in the electrodynamometer. Moving coil moves the pointer with the help of spring control instrument. A limited amount of current flows through the moving coil so as to avoid heating.
What is electrodynamic type instrument?
Electrodynamic type instrument is used for the measurement of AC and DC quantities unlike PMMC instrument which can only be used for the measurement of DC quantity. This type of instrument is known as Elctrodynamometer type instrument. Construction of Electrodynamic Type Instrument
What is an air cored electrodynamometer?
Air cored electrodynamometer instruments are protected against external magnetic fields by enclosing them in a casing of high permeability alloy. This shunts external magnetic fields around the instrument mechanism and minimises their effects on the indication. Laboratory standard instruments are usually contained in high polished wooden cases.