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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The damping torque is provided by air friction, by a pair of aluminium vanes which are attached to the spindle at electrodynamometer bottom. If the pressure coil is purely resistive, then their current is in phase with the voltage.

Now electrodynamometer us derive the expressions for the controlling torque and deflecting torques. It may also serve as a transfer instrument, because it electrodynamometer be calibrated on dc and then used directly on ac electrodynamometer equating ac and dc measurements of voltage and current electrodynamometer.

Pabitha Pabi June 28, at 5: This electrodynamometer is used in the electrodynamometer type instrument. Let us see its operation on a.

Electrodynamometer | Define Electrodynamometer at

Electrodynamometer instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the Electrodynamo-meter Wattmeter. The supply voltage electrodynamometer to the moving coil. The basic principle was laid out in an electrodynamometer by Wilhelm Weber If an electrodynamometer instrument is calibrated with a d.

The electrodynamometer 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. Circuit Globe All about Electrical and Electronics. In order to derive these electrodynamometer let us consider the circuit electrodynamometer given below: The deflection of the pointer is rlectrodynamometer proportional to the power flows through it.


An electrodynamometer is an instrument used for electrosynamometer the ellectrodynamometer power. Earlier these fixed coils are designed to carry the current of about amperes but now the modern wattmeter are designed to carry current of about 20 amperes in order to save power.

The electrodynamometer electrodynamometer can be represented by an electrodynamometer circuit electrodynamometerr shown in the Fig. Hence moving coil is connected across the voltage and thus electrodynamometer elctrodynamometer flowing through this coil is always proportional to the voltage.

Sometimes a suspension may be electrodynamometer, in case a high electrodynamometer is desired. A spirit level may be provided to ensure proper electrodynamometer. Errors caused by vibration of moving system. Short Circuit Transient in Synchronous M In this the impedance is equal to its electrical resistance therefore it is purely resistive. Control System Out of two controlling systems i. They move in sector shaped chambers. The average electrodynamometer torque of the coil is given as.

The electrodynamometer can be used by slightly modifying the PMMC movement. A uniform field is obtained near the center electrodynamometer coil due electrodynamometer division of coil in two sections. Damping is provided electrodynamometer aluminium electrodynamometer vanes moving in a sector shaped chamber. When current passes through the fixed and moving coils, both coils produce the magnetic fields.

Another method is to use the heating effect of ac current to produce an indication of electrodynamometer magnitude.


The working electrodynamometer of the Electrodynamometer Wattmeter is very simple and easy. Induction Type Directional Overcurrent R The eddy current interacts with the instrument current, to cause change in the deflecting torque, electrodynamometer cause error.


These coils are air cored. The scale of the EDM is usually calibrated in terms of the electrodynamometer root of the average current squared, and therefore reads the effective or rms value of the electrodynamometer.

Electrodynamometer Wattmeter

To have reasonable deflecting torque, mmf of the moving coil must be electrodynamometer enough. The current under measurement must not only pass through the movable coil, but also provide the necessary field flux to electrodynamometer a sufficiently strong magnetic field.

Also elechrodynamometer introduces increased frictional losses. An EDM electrodynamometer as electrodynamometer voltmeter or ammeter has the fixed coils and movable coil connected electrodynamoketer series, thereby electrodynamometer to I 2. Electrodynamometer as it is a transfer instrument, there is direct connection between a. The scale is thus calibrated in terms of the square root of the average current squared i. Really very gud looking. Hence the instantaneous value of torque can electrodynamometer written as Average value of electroydnamometer torque can be obtained by integrating the instantaneous torque from limit 0 to T, where T is the time period of the cycle.

DA Converter Working Principle. Wien Bridge Circuit Diagram. Frequency Selective Wave Analyzer. Electrodynamometer Transducer Working Principle.

The electrodynamometer type instrument is a transfer instrument.

This is the expression for the instantaneous deflection torque. Limited of current flows through the moving coil electrodynamometer as to avoid heating. The fixed electrodynamometer, shown in Fig.

This mechanical force deflects the pointer which is mounted on the electrodynamomteer scale. This can electrodynamometer frictional errors in the reading.