Difference between Electrodynamometer Wattmeter and Low Power Factor Wattmeter

Electrodynamometer wattmeter and Low Power Factor (LPF) wattmeters are mostly similar in construction and operation, except for the following modifications are carried out in the electrodynamometer wattmeter to convert it into a LPF wattmeter: Pressure coil resistance is kept low to increase the torque. Compensating coil is used to compensate the Pressure coil current. Capacitor … Read more

Parallel Operation of Single Phase Transformers

Parallel operation of two or more Transformers means that all the Transformers Primary is connected with the common supply and their Secondary are feeding to a common bus through which load is connected. Parallel operation of Transformers requires that their Primaries as well as Secondaries are connected in parallel. Parallel operation of two or more … Read more

Local Breaker Back-up (LBB) or Breaker Failure Protection

Local Breaker Back-up Protection or LBB protection is provided to ensure the healthiness Power System by isolating the faulty section in case of failure of tripping of Breaker intended for tripping on sensing fault. This protection is also called Breaker Failure Protection.   Figure above shows the single line diagram of one and half breaker … Read more

Concept of Transformer Action

The working principle of Transformer is based on Faraday’s Law of Electromagnetic Induction. In a transformer, an alternating magnetic flux is generated in the core by the primary current. This alternating flux links with the secondary winding. As this flux linkage in secondary is time variant, an emf is induced across the terminals of secondary … Read more

How to Find RMS Value of any Function?

 I am writing this post for those who are going to appear for the GATE-2019. If you see the Previous Year Question Papers, you will find that finding RMS for a composite wave or for an arbitrary function is asked frequently. Therefore it is quite important to know “How to find RMS value”. I will … Read more

Suppression of Harmonics in Transformer

In this post we will focus on various methods adopted to suppress harmonics in a Transformer. Harmonics in a Transformer can be suppressed by flowing methods: Lower Flux Density: Harmonics in Transformer can be suppressed by having lower flux density in core but it has one disadvantage that, this method of reducing flux density in … Read more

Voltage Regulation of a Transformer

Voltage Regulation of Transformer is defined as change in magnitude of Secondary Terminal Voltage per unit Rated Secondary Terminal Voltage when load at a given Power Factor is reduced to zero while maintain the Primary Voltage constant. Lets us assume that,   V2 = Secondary Terminal Voltage at any Load   E2 = Secondary Terminal … Read more

Balanced Star to Delta & Delta to Star Conversion

As we know any balanced Star connected system can be completely replaced by an equivalent Delta connected system. This means that a three phase Star connected balanced system having line voltage VL and line current IL can be replaced by an equivalent Delta connected system having phase voltage VL and phase current IL / 1.732. … Read more

Star Delta & Delta Star Conversion

Star-Delta and Delta-Star conversion concept is very basic but most important concept for Electrical Engineers. Be it day to day calculation or solving some numerical of competitive exam, we definitely need this conversion. In this post we will be discussing this Star to Delta and Delta to Star Conversion. For understanding this conversion, we will … Read more