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 hour.

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 frequency

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)