No item in cart
Analysis of Harmonics due to nonlinear core at no load | Electrical Machines | GATE Preparation | EE
Real Life Application
The application of magnetizing curve of non-linear core in transformers is very important in the design of the transformer connection, wherever a transformer is to be installed. The induced emf, the load current, the source current, the magnetic flux waveforms depend on the type of connection in the transformer. For example: 1 phase transformer or Star- Star isolated or Star(grounded)-Delta etc. are some of the possible connections of a transformer. Now, harmonic content of a waveform will depend on the shape of the waveform. Thus, understanding the relationship of connection (transformer) and the waveform of these quantities is important.
The relation between the magnetic field intensity, H and the magnetic flux density, B can also be expressed as the magnetic permeability μ=B/H and the relative permeability: μr =μ/μo. The relative permeability of vacuum, air, diamagnetic substance and paramagnetic substance is constant. Thus the relationship between B and H is linear. The relative permeability of ferromagnetic materials is not constant, but depends on H. In ferromagnetic materials, the relative permeability increases with H to a maximum, then it saturates.
When AC supply is given to the ferromagnetic core, Hysteresis Loop (B-H curve) is formed. Here, the B and H have non-linear relationship. (Magnetic flux waveform will be similar to magnetic flux density waveform and magnetizing current waveform will be similar to that of magnetic field intensity). Then, either the magnetic flux waveform or the magnetizing current waveform will be sinusoidal, as they have non-linear relationship. Now, whether the magnetizing current will be sinusoidal or not, will depend on, whether the path for third harmonics is present in the connection of the transformer or not. Third harmonics has similar property to that of zero sequence current. Basically, both need a closed path to exist. If the flux waveform is sinusoidal then, the magnetizing current will be of peaky shape. If the magnetizing current is sinusoidal then, the flux waveform will be of flat-topped shape or also called camel-hump shape.
THE GATE Academy questions covered a wide variety of topics and were similar to GATE paper standard. The online platform replicated the actual GATE test environment and the detailed and video solutions were sufficient to clear all doubts regarding the question. Thanks to THE GATE Academy team to provide such wonderful tests & platform.
E Lectures helped me a lot in making a head start in the right direction. It helped whenever I got stuck in any topic. Mock Tests across 50 centers helped me judge my progress both on individual and comparative basis.
I am Praveen. I got AIR 1 in Instrumentation stream. I want to dedicate this to my parents and to the Gate Academy faculty. Gate Academy coaching helped me tremendously to update myself continuously.I was very impressed with the way they taught each topic in different sessions with separate material for each session.
I took up mechanical coaching at THE GATE ACADEMY as there is no separate coaching for Engineering Sciences in India and Mechanical and Engineering sciences have more or less common topics.I feared that cracking GATE would be very difficult because I started my preparations very late but the counsellors and teachers guided me
In one year’s time, I was able to prepare for GATE exam with the help of THE GATE ACADEMY and faculties. GATE Focused study materials and online mock tests helped me know my strengthen & weakness to prepare accordingly. I wish all the best to all GATE aspirants and suggest them to go through GATE coaching in case the basics are not clear.
To begin with, it gives me immense pleasure to Thank,Thank the institute THE GATE ACADEMY for all their help and support.Its a place to learn, explore, grow and succeed.Well it helps you brush-up your engineering knowledge and learn new things and clears your concept in such great details
GATE Success Story
- Our students get all India rank 1, 1, 1, 1, 4 and 4
- More than 142 students in top 100.