Dot Convention in Coupled Circuits

Dot Convention in Coupled Circuits: Dot Convention in Coupled Circuits is used to establish the choice of correct sign for the mutually induced voltages in coupled circuits. Circular dot marks and/or special symbols are placed at one end of each of two coils which are mutually coupled to simplify the diagrammatic representation of the windings […]

Mutual Inductance of Coupled Circuits

Mutual Inductance of Coupled Circuits: Mutual Inductance of Coupled Circuits – A voltage is induced in a coil when there is a time rate of change of current through it. The inductance parameter L, is defined in terms of the voltage across it and the time rate of change of current through it υ(t) = […]

Coupled Circuits Definition

Coupled Circuits Definition: Two circuits are said to be ‘coupled’ when energy transfer takes place from one circuit to the other when one of the circuits is energized. There are many types of Coupled Circuits like conductive coupling as shown by the potential divider in Fig. 10.1(a), inductive or magnetic coupling as shown by a […]

Effects of Harmonics

Effects of Harmonics: The relationship between line and phase quantities for wye and delta connections as derived earlier are strictly valid only if the source voltage is purely sinusoidal. Such a waveform is an ideal one. Modern alternations are designed to give a terminal voltage which is almost sinusoidal. But it is nearly impossible to […]

Reactive Power with Wattmeter

Reactive Power with Wattmeter: We have already seen earlier that the difference between higher reading wattmeter and lower reading wattmeter yields VLIL sin Φ. So, the total reactive power = √3 VLIL sin Φ. Reactive Power with Wattmeter in a balanced three-phase load can also be calculated by using a single wattmeter. As shown in […]

Leading Power Factor Load

Leading Power Factor Load: Suppose the load in Fig. 9.46(a) is capacitive, the wattmeter connected in the leading phase would read less value. In that case, WR will be the lower reading wattmeter, and WY will be the higher reading wattmeter. Figure 9.48 shows the phasor diagram for the Leading Power Factor Load. As the […]

Power Factor by Two Wattmeter Method

Power Factor by Two Wattmeter Method: When we talk about the power factor in three-phase circuits, it applies only to balanced circuits, since the power factor in a balanced load is the power factor of any phase. We cannot strictly define the power factor in three-phase unbalanced circuits, as every phase has a separate power […]

Three Wattmeter and Two Wattmeter Method

Three Wattmeter and Two Wattmeter Method: In this method, the three wattmeter are connected in the three lines as shown in Fig. 9.45, i.e. the current coils of the three wattmeter are introduced in the three lines, and one terminal of each potential coil is connected to one terminal of the corresponding current coil, the […]

Power in Three Phase Circuits

Power in Three Phase Circuits: Measurement of power by a wattmeter in a single phase circuit can be extended to measure Power in Three Phase Circuits. From earlier Section, it is clear that we require three wattmeters, one in each phase to measure the power consumed in a three-phase system. Obviously, the total power is […]

Power Measurement in Single Phase Circuit by Wattmeter

Power Measurement in Single Phase Circuit by Wattmeter: Wattmeters are generally used to measure power in the circuits. A wattmeter principally consists of two coils, one coil is called the current coil, and the other the pressure or voltage coil. A diagrammatic representation of a wattmeter connected to measure power in a single phase circuit […]