ELECTRODYNAMOMETER WATTMETER PDF
Electrodynamometer Wattmeter consists of two coils, pressure coil (PC) and current coil (CC). Pressure coil is connected across the circuit. ELECTRODYNAMOMETER. WATTMETER’S. • These instruments are similar in design and construction to electrodynamometer type ammeters and voltmeters. Before we study the internal construction of electrodynamometer wattmeter, it very essential to know the principle of working of electrodynamometer type.
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Gravity control 2 Spring control, only spring controlled systems are used in these types of wattmeter.
Out of two controlling systems i. Due to this current proportional to supply voltage flows through the moving coil.
Scale 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.
Thus we see that, angular deflection of electrodynamometer is proportional to the active power being measured.
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 transferred from one circuit to another circuit. It uses for measuring the power electrodynamommeter both the AC and DC circuits. Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power; other types are required for radio frequency measurements. Now the reason is very obvious of using two fixed coils instead of electroxynamometer, so that it can be constructed to carry considerable amount of electric current.
The device consists of a pair of fixed coilsknown as current coilsand a movable coil known as the potential coil. Instruments of this type are used throughout the RF spectrum waattmeter can even measure visible light power.
In this the impedance is equal to its electrical resistance therefore it is purely resistive.
Wattmeter – Wikipedia
BE Notes r notes. The working principle of the Electrodynamometer Wattmeter is very simple and easy. As discussed earlier in the post, a series resistor is used in PC to limit the current upto mA. The wattmeter is an instrument for measuring the electric power or the supply rate of electrical energy in watts of any given circuit. In fact, a watt meter is a package of an ammeter and a voltmeter, because the product of voltage and current is the power, which is the measurable quantity of a watt meter When current flows through the current coils, then automatically a magnetic field is developed around those coils.
December Learn how and when to remove this template message. Pressure coil is connected across the circuit whose power is to be measured and current coil is connected in series. A typical wattmeter in educational labs has two voltage coils pressure coils and a current coil.
This particularly affects low power e.
Electrodynamometer Wattmeter – Construction | Electrical Concepts
Electronic wattmeters are used for direct, small power measurements or for power measurements at frequencies beyond the range of electrodynamometer-type instruments. They can be used for both to measure AC as well as DC quantities as scale is calibrated for both Errors in Electrodynamometer Type Wattmeter Following are the errors in the electrodynamometer type watt meters: Electrodynamometer Wattmeter are often used for the measurement of power consumption.
These types of instruments are only used for measuring the dc quantities as if we apply ac current to these type of instruments the […]. Learn how your comment data is processed.
Fixed coil or CC is carries the circuit current. Now let us derive the expressions for the controlling torque and deflecting torques. Electrodynamometer Type Electrodynamomeetr 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 transferred from one circuit to another circuit.
Air friction damping is used. Now let the applied value of voltage across the pressure coil be Assuming the electrical resistance of watmteter pressure coil be very high hence we can neglect reactance with respect to its resistance.
Where, x is the angle. 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 construction of such instrument similar to electrodynamomteer construction of electrodynamometer type ammeter and voltmeter. The real power divided by the apparent volt-amperes VA is the power factor. When current flows through the current coils, then automatically a magnetic field is developed around those coils.
There are two types of coils present in the electrodynamometer. Hence moving coil is connected across the voltage and thus the current flowing through this coil is always proportional to the voltage. Let the rms voltage of circuit is V and current flowing is I. As a high value of series resistance is connected in series with the PC, therefore PC circuit can be assumed purely resistive.