Ee6351 electrical drives and controls edc syllabus unit i introduction. Drives are employed for systems that require motion control e. Cooling and ventilation requirements variable speed drives. In some countries nearly 65% of the total electric energy produced is consumed by electric motors. Elements of controlled electrical drive figure 1 shows the structural block diagram of a controlled electrical drive. Dc motors play a significant role in modern industrial drives. If the analysis shows that the heating of the engine is close to or equal to the normative one, this indicates a good use of the engine power, i. In this study, three simulation approaches namely computational fluid. High voltage power supplies for iter rf heating and. Cooling of the electric traction drive machines in some vehicles.
Ramakant srivastava passive sign convention psc passive sign convention deals with the designation of the polarity of the voltage and the direction of the current arrow in an element or a subcircuit. Electrical rules and calculations for airconditioning systems, which will list, explain, and discuss with examples all the topics covering the electrical rules and calculations for airconditioning systems which will include but not limited to the following points introduction for airconditioning systems types. Convective heat transfer coefficients of automatic. Department of electrical engineering basic electrical engineering 4 credit course code. Electrical machines, drives and power systems 6th edition by theodore wildi and a great selection of related books, art and collectibles available now at. Cooling of electric machines article about cooling of. One consideration of this selection process is managing. The design of the iter electrical distribution systems will take into account the requirements of the hvps in terms of requested power and shall comply with the iec. Rating and heating of electric drives, power loss, heating and cooling of motors. In electric drives the driving equipment is an electric motor. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Heating and cooling curves this figure shows the variation of motor temperature rise with time during heating and cooling. One approach to cooling the electric machine includes a cooling water jacket incorporated into the housing that surrounds the stator.
This paper describes a numerical simulation of thermal discharge in the cooling pool of an electrical power station, aiming to develop generalpurpose computational programs for grid generation and flowpollutant transport in the complex domains of natural and artificial waterways. We know that when an electrical motor and drive operates, there is a generation of heat inside the motor. Variable speed drives and soft starters are available in different types of enclosures like most electrical equipment to suit the environment which they are to be installed. It is straightforward to nd i2 using network techniques. The water jacket is typically cooled with a mixture of waterethylene glycol weg. The main components of an electrical drive system can be seen in figure 3. The network of power transistors of a small inverter drive is actually one.
The most efficient method of heat removal is to cool the heated parts. You can find them in factories, automobiles, airplanes, robots and even your favorite dvd vending machine. An inverter drive vfd works by taking ac mains single or three phase and first rectifying it into dc, the dc is usually smoothed with capacitors and often a dc choke before it is connected to a network of power transistors to turn it into three phases for the motor. Heating and cooling curves of electrical drives cooling time. Massachusetts institute of technology mit opencourseware.
In most of the electrical drives, the electrical time constant of the motor is negligible compared with the mechanical time constant. Pdf ee6351 electrical drives and controls edc books. This paper presents the energy losses, heating or cooling of the homogeneous body of electrical machine during its operation. Heating and cooling curves april 23, 2015 chemistry cp 1. The various electrical conductors that form the motor stator windings must be electrically insulated from each other and from the metal parts of the motor structure.
Numerical research on flow and thermal transport in. A piece of equipment that carries or controls electrical energy as its primary function, such as a switch, receptacle, or circuit breaker. Among different options, direct cooling system is studied further and compared to indirect cooling system. In this lecture note only the one axle drives are explained. The main interfaces of the hvps outside the ec and ic plants boundaries are with low 230400 v and high 22 kv voltage electrical distribution, cooling water system and building. Electrical, insulation and thermal measurements for motors. Electrical rules and calculations for airconditioning. Thermal network model of electrical motor by lumped heat method 1vijay mehta, 2sanket pandya, 3nirav meghpara 1assistant professor, 2 assistant professor, 3 assistant professor.
An accurate prediction of heating and cooling curves of electrical drives rise inside an electrical motor is very difficult owing to complex. The material of the motors and the shapes and size of the motors are not unique but the generation of heat does not alter very much depending. Abstract electrical machines is widely used in industry for manufacturing the components or running the plant utilities. What are the various function performed by an electric drive. The maximum permissible heating is determined by the heat resistance of the materialsinsulation, solder, and lubricantused in the machine. Sathyamoorthi,apeee 201516 ee6361 electrical drives and control uniti introduction basic elementstypes of electric drives factors influencing electric drives heating and cooling curves. Thermal time constants of a motor are far larger than electrical and mechanical time constants.
Motor voltage enclosed ac drives and soft starts by. The following sections will outline the basic electrical concepts. Heating and cooling in semiconductor structures by an. To maintain the current, the source must keep using its energy. Development of an integrated cooling system controller for. How an inverter drive works and controls the speed. Costelloe department of building services engineering, dublin institute of technology, ireland d.
The scope of the book reflects the rapid changes that have occurred in power technology over the past few years allowing the entrance of power electronics into every facet of industrial drives, and expanding the field to open more. Depending on the application, cooling systems can be employed with natural convection totally enclosed nonventilated, forced convection air or liquid cooling, or radiation cooling in the case of electrical machines, operating in vacuum environment, 1. Rating and heating of electric drives, power loss, heating and cooling of motors, classes and duty and selection of motors, drives for specific application like steel, paper, textile mills control of electric drives microprocessor hardware and software for drive system. In order to test a motor drive under various load conditions, you must provide a variable and bidirectional load at the motor shaft. International conference passive and low energy cooling 549 for the built environment, may 2005, santorini, greece thermal efficiency characteristics of indirect evaporative cooling systems b. Insulation is required wherever there is a difference of electrical potential between two 2 conductors. The convention is satisfied when the current arrow is towards the terminal marked positive. An electronic control unit ecu has been designed with a single chip computer. One classification point of view is how many motors axles are operated from one device. Electrical power generation by mechanically modulating. Modern heat extraction systems for electrical machines a. If this curve is read from right to left, it is a cooling curve. Unesco eolss sample chapters electrical engineering fundamentals of electrical drive controls josko deur and danijel pavkovic encyclopedia of life support systems eolss 2.
Electrical machines, drives, and power systems by theodore. As an example, figure 2 shows a series of torquespeed curves for an induction machine operated with a wide range of input frequencies, both below and above its \base frequency. The 3d computational fluid dynamics is the correct alternative for the analysis, concept and for the detailed design of electrical machines as it allows to precisely predict the flow structure around the stator coil ends, the distribution of the cooling medium, the pressure losses, the heat transfer coefficients and temperature distribution. Heating effects of electric current page 1 of 1 we all know that current heats when it passes through a wire. Since michael faraday and joseph henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. This is because a part of the source energy is used in. Electric motors are used in machines and processes all around us. The relay will inhibit and starting until there is sufficient thermal capacity to allow a start to take place. The cooling system for such a vehicle is particularly power costing because it needs to dissipate heat from not only the engine, but also the intercooler and the motor. Kirchhoffs laws, node and mesh analysis, deltastar and stardelta. During transient condition, electrical motor can be assumed to be in electrical equilibrium implying that steady state speed torque curves are also applicable to the transient state operation. Thermal model of motor for heating and cooling an electrical motor and drive operates. When a machine is switched off from the mains or when the load on the motor is reduced, the machine cools.
Better working conditions as the radiation losses are low, working with electric furnaces is convenient and cool as well as these furnaces provide noiseless. The type of enclosure supplied is based on the level of protection offered against water and objects, known. Common methods for providing cooling or heat dissipation. For troubleshooting electrical equipment and control circuits, it is important to understand the basic principles on which the electrical equipment works. Drive motor characteristics mechanical characteristics speedtorque characteristics of various types of load and drive. The five electrical resistance heating erh projects at the navy and the national aeronautics and space administration nasa sites provide a wealth of information on the performance of this remediation technology under different site conditions, and the lessons learned from these early applications serve as a good guide for future users. In general, when an electric motor operates, it develops heat as a byproduct. Thermal efficiency characteristics of indirect evaporative. The amount of heat generated inside the motor should be known as accurately as possible. Basic elements types of electric drives factors influencing the choice of electrical drives heating and cooling curves loading conditions and classes of duty selection of power rating for drive motors with regard to thermal overloading and load variation factors. Thermal network model of electrical motor by lumped heat.
Electric motor cooling and heating heating time constant. Mechanical coupling of two motor drives introduction. Electric motors are often selected based upon a particular work or load requirement. An insulation multimeter like the fluke 1587 can perform most of the other tests you need to troubleshoot and maintain motors. Electrical, insulation and thermal measurements for motors and drives insulation multimeters and thermal imagers. Thermal motor model the analysis of the thermal state of the engines allows us to estimate the degree of its power loading. Overheating and cooling of electrical machine is analyzed in analytical and graphical way depending on the temperature of the homogeneous body and accumulation thermal time constant. Regardless of the application, managing heat dissipation is a common theme. We want to find out why, current heats the wire and what is the amount of heat generated. Cooling of electric machines the removal from electric machines of the heat liberated as a result of magnetic, electric, and other losses. This bestselling book employs both a theoretical and practical approach to give readers a broad understanding of modern electric power. Thermal analysis of electric motors in engine cooling fan.
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