Many of the procedures and tips are also applicable to larger motors. These tests include an insulation spot test, a dielectric absorption test, and an insulation step voltage test. If the power source is not connected or bad contact, the motor will not revolve. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. The singlephase ac induction motor best fits this description. Induction motors were invented by nikola tesla in 1888 while he was a college student.
Pdf fault detection techniques for induction motors researchgate. Diagnostics of rotor and stator problems in industrial. A threephase induction motor problem enginuity systems. If the motor is a replacement, verify that the rating is the same as old motor. Induction motor fault heading fault causes remedies induction motor a no supply voltage b driven equipment jam c motor shaft jammed.
The premium efficiency motor selection and application guide and its companion publication, continuous energy improvement in motordriven systems, have been developed by the u. Types of motors the types of motors applicable to this article are ac, single and threephase, squirrel cage, and induction. Find the percentage slip and number of poles of the induction motor. At this moment, the electrician must inspect the switch. A motor may require additional or more frequent attention if a breakdown would cause health or safety problems, severe loss of production, damage to expensive equipment or other serious losses. The 3phase set of currents, each of equal magnitude and with a phase. Also the foundation of pump a foundation of motorpump must be rigid and secure to provide adequate support.
Motor and motor control troubleshooting techniques. Fault detection in induction motors based on artificial. The table below gives the commonly encountered problems in 3 phase squirrel cage induction motors, cause of problems and what remedy to apply to bring the motor back to production. Troubleshooting techniques help keep ac induction motors running. If the previous motor was a special design, a stock motor may not be able to duplicate the performance. Perform a visual inspection to assess the general condition of the motor. Photographs are required in some cases prior to disassembly of the motor to. The various faults in induction machines can result in drastic consequences for an industrial process. Motor overloadedthermal protector continuously drips. The following is some common faults and troubleshooting method of threephase induction motors for your reference. Troubleshooting with insulation resistance test instruments. Note that this article is about troubleshooting threephase motors and drives.
The rotor will constantly be turning to align its magnetic field with that of the stator field. Telecommunication engineering, southwest jiaotong university, china, 2005 thesis submitted for the degree of masters of engineering science in school of electrical and electronic engineering the university of adelaide, australia august 2010. Induction motor a no supply voltage b driven equipment jam c motor shaft jammed. In this case, it is better to choose a induction motor with a great capacity or reduce the load. Speed of this motor is given by the following relation. Is the problem in the motor, or the starting circuit.
Installation, operation and maintenance instructions for ac induction motors 56 6800 frames nema 63 280 frames iec marathon electric contact motor customer service at. All ecm motors slight cogging or rocking is inherent to all ecm motors motor is finding its location between stator and rotor and is determining rotation rumbling sound during startup and shutdown system mechanical resonance approx 300400rpm, three 3 permanent magnets stators cause the rotor to have a. Synchronous and asynchronous ac inductionasynchronous motor an induction or asynchronous motor is an ac electric motor in which the electric current in the rotor needed to produce torque is induced by electromagnetic induction from the magnetic field of the stator winding. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention.
Threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. Sample troubleshooting chart 3phase induction motor 20k pdf. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. In the present day, induction motors consume between 90 to 95 percent of the motor energy used in industry.
Nov 18, 2015 repair and refurbishment of ac induction motors the repair and refurbishment of an ac induction motor should include the following steps. However, it suffers from the disadvantage of a low starting torque. The frequency of routine service varies widely between applications. Motor troubleshooting chart 100 continued motor may have too much endplay. Slide each bearing in using your fingers to position them correctly. Maintenance and troubleshooting three phase induction motor. Problems and premature failures often indicate input power system troubles, poor or deteriorating mechanical installations, or malfunctions in the driven machinery. Maintenance and troubleshooting of electric motors reliance electric posted 11005 motor maintenance scheduled routine care introduction the key to minimizing motor problems is scheduled routine inspection and service. Including the motors in the maintenance schedule for the driven machine or general plant equipment is usually sufficient. By far the most commonly used ac motor is the induction motor. Diagnostics of rotor and stator problems in industrial induction motors. A threephase induction motor problem this application note describes how to set up, solve, and analyze the results of a twopole, threephase induction motor using rmxprt. Smear a little lubricant on your cloth and wipe the area where the bearings were.
Since their construction is so simple and quite robust, there is little to go bad. Gather up any background material you may have on hand and then use your senses to inspect the site. It is comparatively easy to obtain the required speed through the use of motors directly connected to the driven machine, through speed reducers, or the now more economical geared motors, or even through vbelt or chain or sprocket drive. Essential for anyone who needs to buy, install, troubleshoot, maintain, or repair small to industrialsize electric motors, this practical guide contains new information on threephase motors along with coverage of the. Properly installed and maintained lincoln electric polyphase ac induction motors operated within the nameplate ratings will run troublefree for many years. Therefore, motor troubleshooting involves the entire system, not just the.
It is logical that the least expensive, lowest maintenance type motor should be used most often. For example, if the motor has two poles, then at 50 hz frequency motor rpm will be 3000 rpm. Overload relays take the motor off during full load operation. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. In the first part of our presentation, we are going to discuss. Electric motor maintenance and troubleshooting, 2nd edition. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. If the motor is used in an application that is critical to the operation or production, testing is usually limited to checking the voltage at the motor. No matter how urgent the problem and motor failure can cause some very urgent problems always develop a plan of attack before you start repair work. Sizes range from cframe up through the twodigit frames 42, 48 and 56. The acoustic noise in induction motors has three main sources. Pdf induction motors are used worldwide as the workhorse in industrial. Starting switch may be defective, preventing the motor from coming out of start winding.
Put the top half of the ac motor casing back on the bottom half. Most of single phase induction motors use squirrel cage rotor as it has a remarkably simple and robust construction enabling it to operate in the most adverse circumstances. The model created by rmxprt will then be used as an input for empulse as a basis for performing more detailed analysis and for increasing the accuracy of the performance pre. Troubleshooting threephase motors the extent of troubleshooting a 3o motor is dependent upon the motors application. The very first thing that you should do before starting any type of maintenance on a motor is a visual inspection, a lot of times the trouble can be found just by looking, because if the problem is that bad then it should be very obvious by observation. The keys to successful motor operation include a total understanding of the application, then choosing the proper type of motor for the application. Electric motors are essential components in most industrial processes. Electric motor maintenance and troubleshooting, second edition explains in detail how all types of ac and dc motors work. This troubleshooting guide can also be applied to other types of three phase induction motors. Installation, operation and maintenance instructions.
Many of these particularly the shaded pole variety are even protected from burnout if the motor should stall something gets caught in a fan or the bearings seize up, for example. Pdf induction motor fault diagnostic and monitoring methods. Department of energy doe office of energy efficiency and. There must be no vibration, twisting, misalignment etc.
The basic idea of an electric motor is to generate two magnetic fields. The main problems are related to rising costs, worsening conditions in the process, and safety and quality of the. Troubleshooting the problems 1, 2 as mentioned above, open the motor to find out the breakage and weld it. Insulation spot test an insulation spot test is an insulation resistance test that can be used to verify the condition of the insulation over the life of the motor. The modern electric motor installation the individual motor drive has practically replaced all other types.
Induction motor analyses internationalteam workshop problem 30. May 01, 2006 troubleshooting techniques help keep ac induction motors running when equipment in your plant malfunctions, you need to isolate the trouble quickly. There are a multitude of singlephase motor combinations. Singlephase motors are found in a long and diverse list of devices like washing machines, mechanical clocks and generators.
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