Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Ac series motors are also known as the modified dc series motor as their construction is very similar to that of the dc series motor. Consequently, the rated output of 100 horsepower should be derated to approximately 82 hp to reduce the possibility of damage to the motor. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. The brushless dc motor, actually an ac motor, is replacing the conventional brushed dc motor in many applications. Gs1 series ac micro drive, enclosed, 120 vac, 12hp with 1phase input, vhz mode, rs485, modbus, 5ka sccr. Its most common application is in such power tools as an electric drill. Applications of threephase induction motors of size varying from half a kilowatt to thousands of kilowatts are numerous. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Every motor will have a rated values of voltage, current, speed and power and frequency for an ac motor. Avoid long exposure in close proximity to machinery with high noise levels. Introduction to ac motors ac motors electronics textbook. Ac motor works on the same principle as i have described for the dc motor, the only difference lies in the split rings. What details a motor nameplate shows and how to use them.
An introduction to electric motors stmicroelectronics. It also shows the phasor representation of the voltage and current. On the other hand ac or alternating current electric motors are used in a completely different process drawing upon the kind of ac motor being used. Describe how a squirrel cage motor is built, and classify it as either an induction motor or a synchronous 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. Small motor rule, open drip proof, single and three phase.
An ac motor is an electric motor driven by an alternating current ac. It is an indication of how much of the input electrical energy is converted to output mechanical energy. The principle of an ac motor is that electric current is applied to electromagnets, creating a rotating magnetic field to convert electrical energy to rotation mechanical energy. Determine motor specs understanding and accurately identifying the environment of your motors application is crucial to selecting the right product. 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. The characteristics of a shunt motor reveal that it is an approximately constant speed motor. This motor is used when large starting torque is required. Mechanical energy what is an electric motor an electric motor is a device converting electrical energy into mechanical energy usually a torque.
These dxf and dwg files were created using millimeters as the unit. Single phase induction motor this singlephase motors are truly twophase machines. Root cause ac motor failure analysis with a focus on shaft. Bonnett, fellow, ieee abstract the squirrelcage inductionmotorremains theworkhorse of the petrochemical industry because of its versatility and ruggedness. Be sure the motor shaft key is captive before the motor is energized. Schematic representation of a sinusoidal voltage of magnitude e applied on a circuit with a resistive load r. It also describes the pm motor parameter measurement procedures. If a seried dc motor has a laminated stator frame, it can run effectively htt l d iki di iki di 667 from an ac supply as well as dc, this is the. Stator with laminated iron core slots with winding bars ring to short. Servo motor ac servosmelservo drive products cad data. For complete product family overview and details, see the indepth section. Difference between dc and ac motors difference between. Before we discuss these modifications, here it is essential to discuss what is the need and where do we need to do modifications. Dc or direct current motors work in particular situations whereby the speed of the motor needs to be externally controlled.
One type of directcurrent motor can also operate on alternating current. The most common type of ac motor being used throughout the work today is the induction motor. This conversion is usually obtained through the generation of a magnetic field by means of a current flowing into one or more coils. Root cause ac motor failure analysis with a focus on shaft failures austin h. Figure 81 shows the motor output torque as a function of shaft speed with full rated voltage applied to the motor. Motor sizing principles dublin institute of technology. Lathes, drills, boring mills, shapers, spinning, and weaving machines series motor. Normally these are visible on the motors nameplate but in any case they will be given in the documentation. Brook crompton electric motors 264 attwell drive toronto, ontario m9w 5b2 18004638917. Difference between dc and ac motors the engineering projects. Low and high voltage electric motors instructions manual for installation operation and maintenance of electric motors date. In general rated values represent the maximum values that the motor should be subjected to in normal use. A synchronous motor is often used where the exact speed of a motor must be maintained.
The higher the percentage, the more efficiently the motor. When the motor is coupled to equipment, ensure that system vibrations are within acceptable limit per iso 108161 to avoid failure of the motor. To show the performance of a motor when connected to a load, a typical speedtorquecharacteristic for a fan is plotted along with the motor speedtorque characteristic in figure 82. Single phase induction motor double revolving field theory the threephase induction motor starting torque inversely depends on the slip this implies that a small positive slip 0. The ac motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field. The applications of woundrotor ac motors are markedly different from squirrelcage ac motors because of the rotor circuits accessibility. Grounding should be in accordance with national and local standards and consistent with sound practice. Aluminum bars are molded on the slots and shortcircuited at both ends with a ring. The figure above shows the family tree of the ac motors described in this chapter. However, it has its limitations, which if exceeded will. Obtaining the ac motors performance characteristic is a matter of inserting different resistance values in the rotor circuit. An ac motor of this type may be part of a pump or fan or connected to some other form of mechanical equipment such as a winder, conveyor, or mixer.
Electric motors and drives fundamentals, types and applications third edition austin hughes senior fellow, school of electronic and electrical engineering, university of leeds amsterdam boston heidelberg london new york oxford paris san diego san francisco singapore sydney tokyo newnes is an imprint of. And, the stepper motor, a digital version of the motor, is driven by alternating current square waves, again, generated by solidstate circuitry. This document explains v parameter settings for the pm motor drive. For ac motors we use continuous rings as shown in image below, they doesnt block the current and the current can move in both directions easily. Model number m800006 outline dimension drawing see figure 4 nameplate data 1 see figure 5 rated frequency 50 hz motor location indoor altitude less than meters relative humidity less than 90% ambient temp 40 degrees c max duty type continuous weight approx. The ac induction motor is well suited to applications requiring constant speed operation. Because dxf files are intermediate files, the data is not fully compatible. An ac motor of this type may be part of a pump or fan or. 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. These instructions do not purport to cover all the details in motors nor to provide for every possible contingency to be met in connection with.
The motor uses a squirrel cage rotor, which has a laminated iron core with slots. The owner of the motor or an authorized agent of the owner 3. Motor selection 123 motor design 123 converter selection 124 10. Its operation is based on the principle that when a current carrying conductor is placed in a. The schematics shows the resultant current i in phase with the voltage v. Some cad software may not read the files completely. Alternating current motors or ac motors are built on the principle that nikola tesla discovered in the late 19th century. The rotor magnetic field may be produced by permanent magnets, reluctance. Explain how this motor can be operated as either a synchronous motor or a plain induction motor. What is common to all the members of this family is that the basic physical process involved in their operation is the conversion of electromagnetic energy. The rotor and stator are each connected from a different power supply, this gives another degree of freedom for controlling the motor over the shunt. A special woundrotor ac motor, however, has controllable speed and torque. Dimensions indicated are valid to 2 decimal places. For instance, a 100 horsepower, threephase motor operating with voltages of 598, 575 and 552 applied at the motor terminals is running with a 4% voltage unbalance 100 x 23575.
Universal universal motors can operate at approximately the same speed and output on either dc or singlephase ac power. Failure to properly ground the frame of the motor can cause serious injury to personnel. Ac motors include single, multiphase, universal, induction, synchronous, and gear motors. Using a checklist, like the one below, will help you determine your motor application requirements to help you better select the optimal motor or gearmotor for your specific needs. The induction motor is made up of the stator, or stationary windings, and the rotor.
1404 727 1533 226 1224 1065 1191 178 538 1308 805 857 423 120 468 1339 1345 1256 138 703 1335 335 792 1397 1236 1076 130 314 1491 926 196 1389 1076 1035