New forms of energy storage systems, hybrid electric passenger vehicles, and other applications not yet envisioned will require electric motors, in some cases motors that. The synchronous speed of the motor is given by equation 1. Electric motor predictive and preventive maintenance guide electric motor failure could result in lost capacity as well as excessive repair and maintenance costs. The handbook of electric power calculationsprovides detailed stepbystep calculation procedures commonly encountered in electrical engineering. The largest collection of symbols in the network in pdf format. Electrical input voltagethe voltage at which the motor is designed to operate is an important parameter. The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. It is true that single phase motors are less efficient substitute for 3phase motors but 3phase power is normally. If the vibration stops, look for an electrical unbalance.
Electric motors are designed for maximum efficiency when operating at or near rated horsepower. Buying an energyefficient electric motor fact sheet pdf. The term motor used in this checklist refers to all kinds of motors ge produced which are stated in section 4 in this document. Nov 30, 2014 electric motors defined as electromechanical devices that convert electrical energy to mechanical energy. Ss 120 x f p 120 x 60 8 900 rpm rotor speed motor slip is known, equation 2. Electric motors for machines and mechanisms mit fab lab. Isbn 9529107285 second edition 2005 the motor guide basic technical information about low voltage standard motors.
Most electric motors are designed to run at 50% to 100% of rated load. Practical electric motor handbook pdf by irving m gottlieb. The speed of an ac motor depends on the frequency of the input power and the number of poles for which the motor is wound. Ac motors are used worldwide in many applications to transform electrical energy into mechanical energy. Read online now motor rewinding procedure ebook pdf at our library. Drives general 4 motor operation with converter supply 6 motor current waveforms 6 discontinuous current 9 converter output impedance. The frame of the motor holds all the parts in place, and unit 76 electric motors.
General instructions purpose of form use form 8936 to figure your credit for qualified plug in electric drive motor vehicles you placed in service during your tax year. Get motor rewinding procedure pdf file for free from our online library pdf file. Thus the torque is proportional 2to i so it gives the highest torque per current ratio over all other dc motors. Whatever motor you have decided to use for your purposes, you will need to transfer the drive from the motor. An electric motor is an electrical machine that converts electrical energy into mechanical energy. These diagrams are current at the time of publication, check the wiring diagram supplied with the motor. Standard voltage for motors built to nema mg 1 1993 are defined in mg 110. Purpose of an electric motor an electric motor is a device for converting electrical power into mechanical power. We wish to describe here two slightly modified models of an electric motor. Note this is the same password you use to save a configuration in. General electric standard motors rated at 60 hz may be successfully operated at 50 hz at reduced voltage and horsepower as shown in the following table.
Thus, the first and most important step in electric motor selection is determining load characteristics torque and speed versus time. Refer to the motor manufacturers data on the motor for wiring diagrams on standard frame ex e, ex d etc. Which electric motor is best suited for a specific application is a decision that you should best make in consultation with our experienced engineers. The expansion of the use of electric motors industrial, commercial and consumer applications is not at an end. In the electric circuit, current and emf are related by ohms law, which is current. A threephase electric motor, 100 hp 75 kw, iv poles, running at 100% of the rated power, with an original power factor of 0. Simotics industrial electric motors provide you with the optimum solution for every application. Italian, russian, english, dutch, simplified chinese, german, french, spanish, brazilian portuguese size. In this post provide you latest and updated 2018 electrical mcq objective questions with answer which are help for preparation all electrical. The speed of an ac motor depends on the frequency of the input power and the number of poles for which the motor. Its simple and reliable operation makes it rather easy to overlook during everyday maintenance practices. Thus, a 10horsepower hp motor has an acceptable load range of 5 to 10 hp. Lv motors we reserve the right to change the design, technical specification and dimensions, without prior notice. This guide provides information on establishing an effective maintenance program to help prevent unexpected motor.
After checking the motor shaft alignment, disconnect the motor from the driven load. Electric motor predictive and preventive maintenance guide. This book, therefore, targets the large body of workers engineers and students reasonably versed in engineering concepts who feel the need for practical insights relating to electric motors. It is true that single phase motors are less efficient substitute for 3phase motors. Like generators, electric motors consist of a stator and a rotor and the three ingredients. Three phase motors are rated 200 volt, 230 volt, 460 volt and 575 volt.
Where the decompressed 3dcad file name differs from the selected product model name the external shape is identical, change the product model name lowercase alphanumeric characters to be used. An electric motor is a device converting electrical energy into mechanical energy usually a torque. Be sure the motor shaft key is captive before the motor is energized. This bulletin, for exxonmobil customers, is intended to serve as a practical guide to the proper lubrication of electric motor. The value of slip in induction motor is can never be zero. In a graphic design program, i simply made sure that the measurements on the diagram matched up to 100% actual. The power mentioned on the name plate of an electric motor indicates a the power drawn in kw b the power drawn in kva. Rotates a number of degrees with each electric pulse.
However, all motors have some basic essential parts, figure 161. The wire, breaker and fuse sizes are provided as a reference for the installer and are based on the 1996 national electrical code. There are factors that can vary considerably from application to application of an electric motor. An introduction to electric motors stmicroelectronics. This catalog covers those devices designed to meet iec standards for protection and control. Electrical engineering objective questions mcq with answer. Unfortunately, its often too late to employ minor repairs when an electric motor. The mechanical energy can be used to perform work such as rotating a pump impeller, fan, blower, driving a compressor, lifting materials etc. Multiply the torque of the motor by the gear ratio to get the output torque.
The handbook contains a wide array of topics and each topic is written by an authority on the subject. In this post provide you latest and updated 2018 electrical mcq objective questions with answer which are help for preparation all electrical engineering exams like gate, ies, jto, psus, rrb jeaen, rrb loco pilot and technicians, ssc je, dmrc, lmrc, isro and other state level engineering exams. Animation showing operation of a brushed dc electric motor. Other members of the family are the direct current dc motor or generator, the induction motor or generator, and a number of derivatives of all these three.
A motor s efficiency tends to decrease dramatically below about 50% load. Electric motors for explosive atmospheres instructions manual for installation, operation and maintenance of electric motors date. We, gepc are committed to supporting all generations of motors. How to calculate torque through a gear reducer it still runs. Partial reprints or reproductions are permitted subject to full acknowledgement. Electric motors should be matched to the load as close as possible. Multiply the output torque by the rated efficiency of the gear reducer, if the manufacturer has published. More than half of all electric energy generated goes to power electric motors. Electric motors and drives fundamentals, types and applications third edition austin hughes senior fellow, school of electronic and electrical engineering, university of leeds. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion. This conversion is usually obtained through the generation of a magnetic field by means of a current flowing into one or more coils. It is therefore used in starter motors of cars and elevator motors p. The output torque of an electrical motor depends on the intensity of the rotor and stator magnetic fields and on their phase relation.
Electrical engineering objective questions mcq with answer free pdf download. Motors with 100 volts, or higher ratings, are used in appliances, automation and in industrial applications. Other members of the family are the directcurrent dc motor or generator, the induction motor. Jun 01, 2018 slip in induction motor is the relative speed between the rotating magnetic flux and rotor expressed in terms of per unit synchronous speed. Avoid long exposure in close proximity to machinery with high noise levels.
This document contains proprietary information of general electric company, usa. In any case, electric motors should be selected to satisfy the dynamic requirements of the machines on which they are applied without exceeding rated electric motor temperature. All wiring should be performed by a licensed electrician or electrical contractor and must meet all applicable codes for the area where. Most electric motors operate through the interaction between the motor s magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor s shaft. Schneider electric offers a complete line of products for the manual control and protection of motors. Also use form 8936 to figure your credit for certain qualified twowheeled plug in electric vehicles discussed under whats new, earlier.
Electric motor converts electric power into shaft power. Since it is rather easy to build a motor suitable for use on two voltages as long as they are in the ratio of 2to1, it is common to specify single phase motors. The electric motor operation is based on the following points. This motor is used when large starting torque is required. The treatment throughout the handbook is practical with very little emphasis on theory. Electric traction cranes, elevators, hair drier, sewing machine problem a 440 v shunt motor has armature resistance of 0. The gv2 and gv3 manual starters and protectors prov ide manual isolation, manu al motor control, and. Machine powered by electricity that converts electrical energy into mechanical energy rotation. Make it real rather than making a template from scratch, or drilling holes based on careful measurements of the motor, i simply made my own paper template based on the pdf file that i already had of the mechanical drawing of the motor. Efficiency usually drops rapidly when an electric motor operates well under the rated horsepower on the nameplate. In thermodynamics terms, this is simply converting work from one form to another. If the motor then operates smoothly, look for the source of noise or vibration in the driven equipment. Search wegspecificationofelectricmotors50039409manual.
At least one of the two magnetic field is generated by a solenoid carrying a current. Backed by 150 years of experience, simotics motors are unrivaled when it comes to reliability, ruggedness, compactness, efficiency, and performance. Overhead transmission lines and underground cables 9. Simple models of an electric motor easytomake models of an electric motor have been shown at the international festivals physics on stage and science on stage, visited by teachers and popularizers of physics and other natural sciences. Using pulleys with electric motors there are many types of electric motor from small battery powered mirror ball motors turning very slowly to large 240v motors able to rotate at speeds in excess of 1400 revolutions per minute rpm. Motor speed relationship the synchronous speed of an ac motor is the speed of the rotating magnetic field set up by the stator winding synchronous speed rpm 120 x frequency divided by the number of poles. For consultation and interpretation of components, devices and electrical and electronic circuit. An electric motor will try to deliver the required power even at the risk of selfde struction. Motor full load amps are taken from motors currently used by champion. Other members of the family are the directcurrent dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. When the motor is coupled to equipment, ensure that system vibrations are within acceptable limit per iso 108161 to avoid failure of the motor. If the disconnected motor still vibrates, remove power from the motor. There are many types of ac motors, but this course focuses on threephase induction motors, the most common type of motor used in industrial applications.
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