211 SRI RAMAKRISHNA MISSION VIDYALYA POLYTECHNIC COLLEGE.

  Differences between Soft Starter & VFD Soft Starter VFD (Variable Frequency Drive) A semiconductor based motor starter capable of safely starting & stopping a motor. Semiconductor based motor starter that can safely start, stop & also vary the speed of the motor. At full speed, the soft starter is bypassed using a contactor.  It operates throughout the whole operation of the motor. It only regulates the AC voltage using thyristors. It converts AC into DC & back into AC of the desired value. It can only vary the supply voltage. It can vary voltage as well as the frequency. It can generate low to medium starting torque. It can generate high starting torque. There are no harmonics generated in the system. It generates harmonics in the system. It does not need any additional filters. It needs filters due to harmonics injection in the line. It is used for constant motor speed application. It is used for variable motor speed applications It is smaller in size as co...

  Rectification is  the process of converting alternating current (AC) into direct current (DC) .  A rectifier is an electrical device that performs this conversion by allowing current to flow in one direction only.  The process of rectification is made possible by diodes, which act as one-way valves within the rectifier.   Here are some things to know about rectifiers: How they work Diodes are electrical components that have different resistances on either side.  In a forward bias, a p-n junction diode allows current to pass, but in a reverse bias, it blocks the current.   Types of rectifiers There are two main types of rectifiers: half-wave and full-wave.  A half-wave rectifier only converts half of an AC cycle, resulting in a pulsating DC output.  A full-wave rectifier uses both halves of the AC cycle, resulting in a more efficient DC conversion.   Uses Rectifiers are commonly used in DC power supplies and high-voltage direct current ...

  Working Principle of Electromagnetic Flow Meter The electromagnetic flowmeter works on the principle of Faraday’s Law of electromagnetic induction.  This law states that when the conductive liquid passes through the magnetic field, the voltage induces across the conductor.  The magnitude of the voltage is directly proportional to the velocity, length of the conductor and the strength of the magnetic field. The magnetic field is generated by the coil which is mounted on the external metallic body of the pipe.  The liquid acts as a conductor and when passes through the magnetic field induce the voltage across the coil. The magnitude of the voltage depends on the velocity of the liquid.

  What is an Electric Vehicle? As the name implies, an  electric vehicle  is a type of vehicle i.e., car or bike, that uses an electric motor to produce the power required for its propulsion. In an electric vehicle, there can be one or more electric motors to propel it. These motors receive  electric power  from an onboard source of electrical energy like batteries, ultracapacitors, fuel cells, etc. In conventional vehicles like cars and bikes, there is an internal combustion engine used to produce power by burning gases or liquid fuels like petrol, diesel, etc. Since, the combustion of petrol or diesel causes several environmental issues such as global warming, air pollution, etc. Hence, it is necessary to find a new concept that can address all these issues. The electric vehicle can be considered the one. Today, industries are manufacturing different types of electric vehicles to meet different driving requirements. Let us now understand the basic structure of...

  Polycrystalline Solar Panels (Poly-SI) You can quickly distinguish these panels because this type of solar panels has squares, its angles are not cut, and it has  a blue, speckled look . They are  made by melting raw silicon , which is a  faster and cheaper  process than that used for monocrystalline panels. This leads to a lower final price but also lower  efficiency   (around 15%) , lower space efficiency, and a  shorter lifespan  since they are affected by hot temperatures to a greater degree. However, the differences between mono- and polycrystalline types of solar panels are not so significant and the choice will strongly depend on your specific situation. The first option offers a slightly higher space efficiency at a slightly higher price but power outputs are basically the same.

  Monocrystalline Solar Panels (Mono-SI) This type of solar panels (made of monocrystalline silicon) is  the purest one . You can easily recognise them from the  uniform dark look  and the  rounded edges . The silicon’s high purity makes it one of the  most efficient solar panels , with the newest ones  reaching above 20% . Monocrystalline panels  have a high power output, occupy less space, and last the longest. Of course, that also means they are the most expensive of the bunch. Another advantage to consider is that they tend to be slightly less affected by high temperatures compared to polycrystalline panels.

  The best type of solar panel Monocrystalline solar panels are the best type of solar panel  in terms of efficiency. Their ability to capture sunlight is higher than both polycrystalline panels and thin-film solar panels. This is also why they are more expensive than  cheap solar panels , which are almost always made from polycrystalline. All black solar panels  and most  integrated solar panels  are monocrystalline in nature. Compared to the process for polycrystalline panels, the structure of the silicon is aligned better in mono panels. As a result, they have higher sunlight absorption rates. Monocrystalline panels are made from pure refined silicon in a pulling process. They can also be produced as “passivated emitter and rear contact” (PERC) panels which gives them the ability to reflect back unabsorbed sunlight through a back cell. This gives them a higher efficiency rate than traditional monocrystalline cells. The most efficient type of monocrystall...

  Working principle of Alternator An alternator or synchronous generator works on the principle of the Faraday law of electromagnetic induction just like in other AC generators.  It states that whenever a conductor moves in a magnetic field, an EMF (electromotive force) or current is induced in the conductor which can be found using the  EMF equation of an alternator.   In other words, a conductor placed in a varying magnetic field also experiences EMF and it is used in alternators. The direction of the induced current is determined by  Fleming’s right-hand rule .  If we arrange the thumb, forefinger and middle finger of the right hand, the thumb direction of motion, the forefinger represents induced current and the middle finger represents the direction of magnetic field lines. Therefore, they are all mutually perpendicular.