Why is 3 voltmeter method used to measure power when power can be from a single wattmeter?
A wattmeter is an instrument which consists of two coils called Current coil and Potential coil. Hence, three wattmeters are required to measure power in three-phase, four-wire system, whereas, only two wattmeters are required to measure the power in 3 phase, 3 wire system.
Why extension of range of energy meter is required?
When using a PMMC meter as an ammeter, its range of measurement can be extended further with the help of parallel connected “Shunt Resistors”, thus allowing it to measure DC currents many times greater than its normal full-scale deflection current rating as only a fraction of the total current will pass through the …
What are the applications of ammeter and voltmeter?
A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. An ammeter is a measuring device used to measure the electric current in a circuit.
What are the application of resistor?
Resistor is used in power control circuit. It is used in DC power supplies. Resistors are used in filter circuit networks. It is used in amplifiers, oscillators, telecommunication and digital multimeter.
Why 3 voltmeter method is used?
The three voltmeter is used in an inductive circuit to measure the value of the power factor. One ammeter is used to measure total current of the circuit, the second one measures current going through the non- inductive resistance and the third ammeter measures the current of the load branch.
Can three wattmeter method be used for unbalanced load?
Two wattmeter method and three wattmeter methods are used for both balanced and unbalanced loads.
Which bridges are used for measurement of inductance?
A Maxwell bridge is a modification to a Wheatstone bridge used to measure an unknown inductance (usually of low Q value) in terms of calibrated resistance and inductance or resistance and capacitance. When the calibrated components are a parallel resistor and capacitor, the bridge is known as a Maxwell-Wien bridge.
What are the practical applications of choke coil?
A choke coil is a part used in electrical circuits to allow DC current to flow through while blocking AC current from passing. These coils are used in a number of electrical devices. When used as part of a radio’s circuitry, it falls into one of two frequency classes: audio or radio.
Why do we use shunt multiplier in DC ammeter?
It is possible to extend the range of an ammeter by using a shunt. This shunt provides a bypath for extra current because it is connected across (i.e. in parallel with) the instrument. These shunted instruments can be used to measure currents many times greater than their normal full-scale deflection currents.
