Concept of Tap-Changers in Transformer

The modern loads are designed to operate at satisfactorily at one voltage level. It is therefore of great importance to keep the consumers terminal voltage within a prescribed limits. The Transformers output voltage and hence the terminal voltage of the consumer can be controlled by using tap either on primary or secondary side of Transformer. … Read more

Per Unit System in Electrical Engineering

Per unit system is a method used in Electrical Engineering for the analysis to express the voltage, current, kVA and impedance in per unit of base or reference values of these quantity. Per Unit values for any system is obtained by choosing a set of some base or reference value which can be chosen arbitrarily. … Read more

Creepage Distance of Insulator

The purpose of the insulator or insulation is to insulate the electrically charged part of any equipment or machine from another charged part or uncharged metal part. Creepage Distance is the shortest path between two conductive parts measured along the surface of the insulation as shown in figure below. When a flashover occurs in the … Read more

Transformer Winding Temperature Indicator

The winding is the component with the highest temperature within the transformer and it is the component which is subjected to the fastest temperature increases as the load increases. Therefore for the control of the temperature parameter within the transformer, the temperature of the winding, as well as top oil, is measured. The temperature of … Read more

Cause of Skin Effect in AC Conductors

The behavior of AC current is different than the behavior of DC current. When DC current flows through a conductor, it get uniformly distributed over the whole cross-section of the conductor but when AC current flows, it has a tendency to flow near the surface of the conductor. This behavior of AC current is popularly … Read more

Difference between Induction Motor and Transformer

As per the equivalent circuit representation, a three phase Induction Motor is generalized transformer but there are some differences between the Induction Motor and a Transformer, they are summarized below. The basic and most important difference is that even though the equivalent circuit of Induction Motor and Transformer is same rotor of motor rotates where … Read more

Why Capacitor is Generator of Reactive Power while Inductor an Absorber? Understanding Reactive Power

Consider an Inductive circuit and assume the instantaneous voltage be v = VmSinωt   Then the current will lag behind the voltage by some angle Ø and the instantaneous current will be as   i = ImSin(ωt-Ø)   Now to understand the concept of Reactive Power, we will calculate the instantaneous power. The instantaneous power … Read more

Why does Induction Motor has Poor Power Factor at No Load

Induction Motor when started at no load has very poor power factor in the range of 0.1 to 0.3. For understanding the effect of loading on the power factor of Induction Motor, we will consider three components of current flowing in an Induction Motor namely Magnetizing Current, Stator Loss Component of Current and Load Component … Read more