EAEP-Electrical and Electronics Portal

Typical view of Speed sensor   What is speed sensor? The speed sensor belongs to the tachometer category. It is a device used to measure the speed of wheel rotation of a vehicle. The speed sensor was initially used to replace the mechanical connection between the rotating wheels and the speedometer, reducing the use of cables and facilitating construction by reducing rotating parts. These sensors also generate data that allows automatic driving to take place. The speed of an object is the magnitude of the change of its position; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed has the dimensions of distance divided by time. The SI unit of speed is the meter per second, but the most common unit of speed in everyday usage is the kilometer per h...

Reed switch What is a reed switch? Magnetic reed switch an electrical switch driven by a magnet. It consists of a pair of ferromagnetic flexible metal contacts in a hermetically sealed glass envelope. There are two types of configuration: Normally open (NO), closes when a magnetic field is brought near and normally close (NC) open when a magnetic field is brought near. When the magnetic field is removed, the contacts in the reed switch return to their original position. It was invented at Bell Telephone Laboratories in 1936 by Walter B. Ellwood. How a Reed Switch Work? The switching mechanism of the reed switch consists of two ferromagnetic blades which are separated by a small gap. These ferromagnetic blades are lightweight, magnetic and flexible. When a magnet is brought close to these blades, the two blades pull towards each other. Once the blades are closed the normally open (NO) contacts that allow electricity to flow. Some reed switches do not have a ferromagnetic contact, such s...

Scheme: A VFD panel view What is variable frequency driver (VFD)? A variable frequency driver (it is also knows as Drives, VFD and inverters) is a type of motor starter that drives an electric motor by changing the frequency and voltage of its power supply. A VFD works according to principle of V / f  policy. The VFD has the ability to control the acceleration and de-acceleration of the motor during start or stop, respectively. These drives are the main reason why the DC motor, which was used extensively in factories in the past, has completely shifted the AC motor from our focus to the essential. VFD has brought the use of AC motors back to important among us. The AC-induction motor can change its speed by changing the frequency and voltage of the power supply used to operate it. This means that if the voltage applied to the motor is 0 Hz, then motor is running at zero speed. When a frequency of 50 Hz is applied to the motor, the motor will run at its rated speed, and if the frequ...

Scheme: Induction motor An induction motor is a machine. Any machine that converts electrical energy into mechanical energy is called a motor. An induction motor works according to the principle of electromagnetic induction. Let us know why it is called induction motor. In a d.c motor electrical energy is conducted directly to the armature (i.e rotating part of the motor) through brushes and Commutator. Hence the d.c motor can be called the conduction motor. Like this in a.c motors, the rotor does not connect to the electrical energy by conduction instead by induction. In this sense, such an electric motors are called induction motors. An induction motor is also called a rotating transformer because this operating principle is consistent with the transformer operating principle. That is, the primary winding is stationary but the secondary winding is rotable.

Hall sensor symbol What is a Hall effect sensor? Hall effect sensor is defined as a device which use the principle to convert magnetically encoded signals into electrical signals. Which means Hall effect sensor output voltage is directly proportional to the magnetic field strength. Hall effect sensors are used in automotive systems for sensing distance, position, speed detection, and current sensing applications.

Star-Delta starter Introduction: According to electromagnetic induction principle, once a supply is connected to a three phase induction motor a rotating magnetic field will be set up in the stator, this will link and cut the rotor bars which in turn will induce rotor currents and create a rotor field which will interact with the stator field and starts rotating. Of course this means that the three phase induction motor is entirely capable of self-starting. Need of starter: The need for a starter therefore is not, but in case of three phase induction motor starter is to provide smooth starting, to reduce Heavy starting currents, provide overload and no-voltage protection.

Scheme: Fluorescent lamp What is Fluorescent lamp? A fluorescent lamp , or fluorescent tube , is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps. The typical luminous efficacy of fluorescent lighting systems is 50–100 lumens per watt, several times the efficacy of incandescent bulbs with comparable light output.                                (by Wikipedia)

Tariff and Economic Considerations Economic Motive:  In all engineering projects with the exception of the construction of works of art or memorial buildings, the question of cost is of first importance. In fact, in most cases the cost decides whether a project will be undertaken or not although political and other considerations may intervene sometimes. However, the design and construction of an electric power system is undertaken for the purpose of producing electric power to be sold at a profit. Hence, every effort is made to produce the power as cheaply as possible. The problem of calculating the cost of any scheme is often difficult because the cost varies considerably with time, tariffs and even with convention. In general, the cost of producing electric power can be roughly divided into the following two portions:

  History of paper a brief: Paper was first discovered in ancient China, and the first material used for writing was a "tree" called papyrus. These papyrus materials are not defined as real paper. It was first documented in China during the Eastern Han period (25-220 CE), usually told to a court official. Spread to the Islamic world during the 8th century. The algorithm of the 11th century was brought to medieval Europe. Later in the 19th century came the Western developments in the field of paper with the invention of wood-based papers.

As for the electrician's kit, the most essential thing for every electrician is that they cannot do without the kit, and the kit is essential to complete the biggest tasks easily and on time. Electrical work cannot be done without the right tools, and some basic tools are essential for every electrician to do their job safely and efficiently. So, we have prepared a short list that they are ‘very essential tools’ that every electrician should have in their tool box. 1. Combination Plier Combination plier source_Taparia It is made of steel and its size is given according to its length. It has a cutter for cutting the wires. It is so named because it is used for multi-purpose, such as cutting, twisting of wire sand holding round and flat jobs. They are either insulated or non-insulated. An insulated combination plier is specially used to work on live conductors where it prevents the current from leaking to the human body.

  Definition of a Logic Gate: "A logic gate is an electronic circuit which makes logic decisions". It has one output and one or more inputs. The output signal appears only for certain combinations of input signals. Logic gates are the basic building blocks from which most of the digital systems are built up. They implement the hardware logic function based on the logical algebra developed by George Boole which is called Boolean algebra in his honour. A unique characteristic of the Boolean algebra is that variables used in it can assume only one of the two values i.e. either 0 or 1. Hence, every variable is either a 0 or a 1.

  What Is a Level Controller? A Conductive Level Controller electrically detects the level of a liquid. Conductive Level Controllers are electronic liquid level detectors used in a wide range of applications such as water and sewer services for office and apartment buildings, industrial applications for iron and steel, food, chemical, pharmaceutical, and semiconductor industries, and liquid level control for agricultural water, water treatment plants, and wastewater plants. When the electrodes are in contact with liquid, the circuit is closed (the liquid completes the path for electricity to flow) and the electrical current that flows in this circuit is used to detect the level of the liquid. A variety of conductive liquids can be controlled using this method. Detecting the resistance between the electrodes and comparing it to see if it is larger or smaller than a reference resistance is used to detect the surface of the liquid.

1.Ohm´s law: The ratio of potential difference (V) between any two points on a conductor to the current (I)  flowing between them, is constant, provided the temperature of the conductor does not change.                               In other words, V/I= constant or V/I= R 2.Kirchhoff´s law´s:  a. Kirchhoff’s Point Law or Current Law (KCL) In any electrical network, the algebraic sum of the currents meeting at a point (or junction) is zero.                               i.e incoming currents = outgoing currents  b. Kirchhoff’s Mesh Law or Voltage Law (KVL) The algebraic sum of the products of currents and resistances in each of the conductors in  any closed path (or mesh) in a network plus the algebraic sum of the e.m.fs. in that path is zero.

Scheme: Solid state relay WHAT IS A SOLID STATE RELAY? A Solid State Relay (SSR) is a relay that does not have a moving contact. In terms of operation, SSRs are not very different from mechanical relays that have moving contacts.  SSRs, however, employ semiconductor switching elements, such as thyristors, triacs, diodes, and transistors.

What Is Limit Switch? A Limit Switch is enclosed in a case to protect a built-in basic switch from external force, water, oil, gas, and dust. Limit Switches are made to be particularly suited for applications that require mechanical strength or environmental resistance.

What is Power Factor? Most loads in modern electrical distribution systems are inductive. Examples include motors, transformers, gaseous tube lighting ballasts, and induction furnaces.  Inductive loads need a magnetic field to operate. 

Scheme: Photoelectric sensor What is photoelectric sensor? A photoelectric sensor is an electronic equipment used to detect absence or presence of an object, and to measure the distance. By using a light transmitter (mostly infrared) and photovoltaic receiver, predicts the distance of a particular object, their presence and absence. And they are often used extensively in the manufacturing industry. The emitter in photoelectric sensors is for emitting the light and the receiver for receiving light. When emitted light is interrupted or reflected by the sensing object, it changes the amount of light that arrives at the Receiver. The Receiver detects this change and converts it to an electrical output. As mentioned earlier, the light source for the majority of Photoelectric Sensors is infrared or ordinary visible light (generally red, or green/blue for identifying colors).

Proximity sensor What is Proximity Sensor? All types of sensors that make contactless detection are known as proximity sensors. But like limit switches you can detect them by physical contact with them. Proximity Sensors convert information on the movement or presence of an object into an electrical signal. There are three types of detection systems for making this conversion: firstly systems that use eddy currents generated in metal-sensitive objects by principle of electromagnetic induction, and secondly systems that detect changes in electrical potential when approaching a sensitive object and systems that use magnets and reed switches. All sensors that provide non-contact detection of target objects that are close by or within the general vicinity of the sensor are known as proximity sensors, and generally classifies them as inductive, capacitive, ultrasonic, photoelectric, magnetic, etc. This Technical Explanation defines all inductive sensors that are used for detecting metallic...

Typical view of Transformer What is Transformer? A transformer is a static or stationary piece of apparatus by means of which electric power in one circuit is transformed into electric power of the same frequency in another circuit. It can raise or lower the voltage in a circuit but with a corresponding decrease or increase in current.

Scheme: DOL starter with panel Direct on Line  (DOL) Starter: The simplest method of starting an induction motor is Direct On line(DOL) starter. The DOL starter consist of MPCB or MCCB, Contactor, over load release and fuse for protection. Thermal over load relay protect the motor from over load.    The starter is controlled by Stop and start push buttons, an auxiliary NO contact is used for holding. Which means contactor is energized even though we release start push button.