211 SRI RAMAKRISHNA MISSION VIDYALYA POLYTECHNIC COLLEGE.

  What is motor efficiency First, let's define what we mean by motor efficiency. Motor efficiency is the ratio of output power to input power, expressed as a percentage. It measures how effectively a motor converts electrical energy into mechanical energy. The higher the efficiency, the less energy is lost as heat or other forms of waste, and the more power is available for useful work. Three common types of motors are DC motors, AC motors, and BLDC motors. Each of these motors has its own advantages and disadvantages when it comes to efficiency. DC Motor Efficiency DC motors are the simplest type of electric motor, and they have been used for many years in a variety of applications. They operate by using a direct current to create a magnetic field that rotates the motor's armature. DC motors are known for their high starting torque and controllability. However, they are also known for their low efficiency, typically ranging from 50-80%. This is due to the energy lost as heat ...

  DC Chopper : This type of chopper circuit is considered to be static that changes fixed dc input voltage into a variable one.  It behaves in a similar manner as that of an ac transformer and executes single-stage conversion in order to convert dc into dc.  This conversion technique is more efficient than the one involved in ac link chopper.

  Block Diagram and Working of SMPS The major components that constitute SMPS are as follows : Input rectifier and Filter (Diode rectifier and capacitor filter) High-frequency switch (Power transistor or MOSFET) Power transformer Output rectifier and Filter (Diode rectifier and capacitor filter) Control circuit (comparator and pulse width modulator) The figure given below represents the functional block diagram of SMPS :

  D C motors are used on trains is  because of their high torque and good speed control . Compared to AC motors, DC motors can provide industry applications with a fine balance of strong starting torque and controllable speed for seamless yet precise performance. Series wound motor : It has a very high starting torque. Hence it is used for heavy-duty applications such as electric railways, mine hoists, continuous conveyors cranes, rolling mills, metallurgical works etc. Electric trains run on DC , the overhead lines carry 25000 volts AC, get converted to DC and drives the series motors for the drive. During early days, the overhead lines carried 1500 volts DC

  What is a Transducer? A transducer is an electronic device that converts energy from one form to another. The process of converting energy from one form to another is known as transduction. Some common examples of transducers include loudspeakers, microphones, thermometers and LEDs. Why do we need a transducer? To determine the exact magnitude of physical forces such as temperature and pressure is difficult. But, if these physical forces are converted into an electrical signal, then their values can be easily determined using a meter. The primary function of transducers is to convert a physical force into an electrical signal so that it can be easily handled and transmitted for measurement.

  The Integrator Amplifier The integrator Op-amp produces an output voltage that is both proportional to the amplitude and duration of the input signal The ideal op-amp integrator is an inverting amplifier whose output voltage is proportional to the negative integral of the input voltage thereby simulating mathematical integration. Operational amplifiers can be used as part of a positive or negative feedback amplifier or as an adder or subtractor type circuit using just pure resistances in both the input and the feedback loop. But what if we where to change the purely resistive (  Rƒ  ) feedback element of an inverting amplifier with a frequency dependant complex element that has a reactance, (  X  ), such as a Capacitor, C. What would be the effect on the op-amps voltage gain transfer function over its frequency range as a result of this complex impedance. By replacing this feedback resistance with a capacitor we now have an RC Network connected across the oper...

  Applications of SCR The SCR can be used in following applications: 1.Power Switching Circuit 2.Controlled Rectifier 3.AC power control circuits 4.Speed control of DC shunt motor 5.SCR Crowbar 6.Computer logic circuits 7.Timing Circuits 8.Inverters 9.Battery Charging Regulators 10.Temperature control systems