# AC fundamentals

## Power Factor Improvement Using Capacitor Bank

All electrical appliances and industrial equipment consume power at a lagging power factor. The power factor of industrial and commercial installations tend to be low, usually ranging between 0.60 – 0.75 only. The overall power factor of any installation is likely to be below 0.7 unless corrective measures are adopted to improve it.   Due …

## Three Phase Power Measurement

In ac circuits, power is measured with the help of wattmeter. A wattmeter is an instrument, which consists of two coils called the potential coil (PC) and the current coil (CC). The potential coil having high resistance is connected across the load and carries the current proportional to the potential difference across the load. The current coil …

## Delta Connection Definition

In this method of interconnection, the dissimilar ends of three phase windings are joined together i.e. finishing end of one phase is connected to the starting end of the other phase and so on to obtain a closed circuit.   The three line conductors are taken from the three junctions of mesh and are …

## Star Connection Definition

Star Connection Definition   In this method of interconnection, three similar ends a’, b’, c’ of the three windings are joined together at a common point. This point is known as star point or neutral point N.   The three conductors meeting at star point are replaced by a single conductor known as neutral …

## Power Factor in AC Circuit

In DC circuits, the product VI gives the power in watts drawn by the circuit. But in AC circuits, things are different. In AC circuits, the product VI gives the apparent power and not the real power because the voltage and current are not in phase with each other.   Power Factor in AC Circuit …

## RC | RLC | RL Series Circuits

In actual practice, AC circuits contain two or more than two components connected in series. In a series circuit, each component carries the same current. An AC series circuit may be classified as under: RL series circuit RC series circuit RLC series circuit RL Series Circuit     In an RL series circuit, a pure …

## Purely Resistive | Inductive | Capacitive Circuit

All AC circuits are made up of the combination of resistance R, inductance L and capacitance C. The circuit elements R, L, and C are known as circuit parameters. To study a general AC circuit it is necessary to consider the effect of each parameter separately.   Purely Resistive Circuit   A purely resistive circuit …

## RMS Value of AC | Derivation

The RMS value of alternating current is given by that steady current (DC) which when flows through a given resistance for a given time produces the same amount of heat as produced by the alternating current when flow through the same resistance for the same time.   For example, if we say that 3A alternating …

## Advantages of AC over DC

The use of DC is limited to few applications e.g. electrolytic processes, electroplating, electronic circuits etc. However for power generation, transmission, distribution and utilization AC system is invariably used.   Advantages of AC over DC   In AC system we can use transformers to change the voltage levels. It cannot be used in DC system. …