and can moves freely. • In electrodynamometer type wattmeter, moving coil works as pressure coil. • Hence moving coil is connected across the voltage and thus. Study of ammeter, voltmeter and wattmeter connections. • To investigate the errors .. an electrodynamometer for use as a wattmeter is shown in Fig. is kep. 5 Nov Electrodynamometer Wattmeter consists of two coils, pressure coil (PC) and current coil (CC). Pressure coil is connected across the circuit.
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In this the impedance is equal to its electrical resistance therefore it is purely resistive. A limited amount of electric current flows through the moving coil so as to avoid heating.
Damping System Air friction damping is used, as eddy current damping will distort the weak operating magnetic field and thus it may leads to error. The controlling torque exerted on the spring is wzttmeter by. Hence moving coil is connected across the voltage and thus the electric current flowing through this coil is always proportional to the voltage.
The scale is mirror type and knife edge pointer to eliminate reading error due to parallax. Scale There is uniform scale electrkdynamometer is used in these types of instrument as moving coil moves linearly over a range of 40 degrees to 50 degrees on either side. The magnetic field in which the lightweight moving coil is situated is generated by passing current through the stationary field coils.
Consequently, current I v through the moving coil is directly proportional to the load electrodynanometer. Ask a Question Submit Now.
The supply voltage applies to the moving coil. Leave a Reply Cancel reply Your email address will not be published. Submit Your Questions Here! Matlab Posted 8 days ago.
Electrodynamometer Type Wattmeter
Leave a Reply Cancel reply You must be logged in to post a comment. The construction of such instrument similar to the construction of electrodynamometer type electrodunamometer and voltmeter.
Therefore they can easily carry heavier current. In a DC Circuit, the power supplied to a load can be determined by measuring the load voltage and current and multiplying them together: The pointer is fixed on the moving coil which is placed electrodhnamometer the fixed coils.
Next Types of Fossil Fuels. Circuit Globe All about Electrical and Electronics. Construction and Working Principle Advantages Errors. The Electrodynamometer Wattmeter waattmeter two types of coils; fixed and the moving coil. Advantages of Electrodynamometer Type Wattmeter Following are the advantages of electrodynamometer type wattmeter and they are written as follows: Errors may be due to mutual inductance effects. When set to 0.
Errors may be due to pressure coil capacitance. Their working depends on the theory that the current carrying conductor placed in a magnetic field experiences a mechanical force.
Electrodynamometer Wattmeter – Construction | Electrical Concepts
The fixed coil connects in series with the circuit whose power consumption use to be measured. Your email address will not be published. Now let us derive the expressions for the controlling torque and deflecting torques.
Control System Out elcetrodynamometer two controlling systems i. Therefore the current flowing through the PC is in phase with the circuit voltage V and given as. Have a Referral code?
Used in Automotive and engineering Where, x is the angle. Scale is uniform upto a certain limit. Errors due to stray magnetic field. There are two types of coils present in the electrodynamometer. So the expression for the torque can be written as: The pressure coil current in a wattmter pf wattmeter may be as much as 10 times the value used for ordinary wattmeters.
The average deflection torque of the coil is given as. Errors in Electrodynamometer Type Wattmeter Following are the errors in the electrodynamometer type wattmeters: Hence the instantaneous value of torque can be written as Average value of deflecting torque can be watmeter by integrating the instantaneous torque from limit 0 to T, where T is the time period of the cycle. Hence the instantaneous value of torque can be written as Average value of deflecting torque can be obtained by integrating the instantaneous torque from limit 0 to T, where T is the time period of the cycle.
Now the reason is very obvious of using two fixed coils instead of one, so that it can be constructed to carry considerable amount of electric current.
Leave a Reply Cancel reply Your email address will not be published. The construction of a dynamometer instrument to some extent resembles the PMMC instrument. Moving coil is called Pressure Coil or simply PC.
Let I 1 and I 2 be the instantaneous values of currents in pressure and current coils respectively. Earlier these fixed coils electrodynaometer 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.
You must be logged in to post a comment. But we know that. Due to this the sizes of earlier wattmeter were large. Gravity controlled system cannot be employed because they will appreciable amount of errors.