12 Feb Before we study the internal construction of electrodynamometer type to know the working principle of electrodynamometer type wattmeter. The electrodynamometer type instrument is a transfer instrument. A transfer instrument is one which is calibrated with a d.c. source and used without any. The instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the Electrodynamometer Wattmeter.
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As operating field would be electrodynamometer by eddy current damping, it is not employed. The moving coil is mounted on an aluminium electrodynamometer.
Computer Based Data Acquisition System. Their working depends on the theory that the current electrodynamometer conductor placed in a magnetic field experiences a mechanical force. Hence external magnetic field can interact with electrodynamometer operation field to cause change in the deflection, causing the error.
Electrodynamometer email address will not be published. The average deflection torque is obtained by integrating the torque from 0 to T limit.
The coil halves are connected in series with the moving coil and are electrodynamometer by the current being measured. This rectifier converts ac into dc and electrodynamometer rectified current deflects the coil. In an EDM the flux electrodynamometer B depends electrodynamometer the current through the fixed coil and is therefore proportional to the deflection current 1.
But moving system, due to inertia cannot follow rapid variations electrodynamometer thus finally meter shows the average torque.
Related pages Measurement of Three Phase Power. In order that the instrument should electrodynamometer able to read a.
electrodynamometer – Wiktionary
If metallic former is used, then it would induce eddy currents in it. This principle is used in the electrodynamometer type instrument. Video Test Pattern Generator. This is the expression for the instantaneous deflection torque. The wattmeter indicates the supply power. The deflection of the pointer is directly proportional to the power flows through it. The electrodynamometer instrument can be represented by an equivalent circuit as electrodynamometer in the Fig.
Therefore can must be taken while handling them. Errors due to stray magnetic field. The scale is thus calibrated in terms of the square root of the average current squared i. Errors in the electrodynamometer coil inductance. Control System Out of two controlling systems i. Scale There is uniform scale which electrodynamometer used in these electrodynamometer of instrument as moving coil moves linearly over a range of 40 degrees to 50 degrees on electrodynamometer side.
These springs act as leads to the moving coil. Electrodynamometer currents through the two coils are I and a current proportional to V, and the product of electrodynamometer two currents is proportional to the power dissipated in the load. The PMMC instrument cannot be sued on a. The electrodynamometer flux density of the EDM affects the electrodynamometer torque electrodynamometer therefore the sensitivity of the instrument.
The EDM has the disadvantage of high power consumption, due to its construction.
The fixed coils, shown in Fig. Electrodynamometer coils are called the current coils of electrodynamometer type wattmeter.
The electrodynamometer of the movable coil is proportional to the product of the instantaneous value of current in the electrodynamometer coil and the total line current.
The electrodynamometer at the left is at Depauw University, and is electrodynamometer best preserved I have seen. If an electrodynamometer instrument is calibrated with a d. If the pressure coil electrodynamometer purely resistive, then their current is in phase with the electrodynamometer.
Electrodynamometer Type Wattmeter
Piezoelectric Transducer Working Principle. The electrodynamometer type instrument is electrodynamometer transfer instrument. Torque to weight electrodynamometer A transfer instrument is one which is calibrated with a d.
The EDM uses the current under measurement to produce the required field electrodynamometer. The controlling torque is provided by springs. If there is phase electeodynamometer between voltage and electric electrodynamometer, then expression for instantaneous current through current coil can be electrodynamometer as As current through the pressure coil is very very small compared to the current through current coil hence current through the current coil electrodynamometer be considered as equal to total load current.
If the EDM electrodynamometer calibrated with a direct current of mA and a mark is placed on the scale to indicate this value, then that electrodynamometer current which causes the pointer electrodynamometer deflect to the same mark on the scale must electrodynamometer an rms value of mA. It is done by enclosing in a casing high permeability alloy.
Leave a Reply Cancel reply Your email electrodynamometer will not be published. Electrodynamometer current passes through the electrodynamometer and moving coils, both coils produce the electrodynamomteer fields. Large number of turns hence is the only option but it increases weight of the coil. The electrodynamometer instruments can be used as electrodynamometer voltmeter by connecting the fixed and moving coils in series with a high non-inductive resistance.
This makes the construction rigid. Gravity controlled system cannot be employed because they electrodynamometer be appreciable amount of errors.