Home technical articles testing and commissioning procedure for electric motors scope of motor testing it should be noted that the scope of motor testing depends upon the motor type and size, this being indicated on the inspection forms. The 22 new motors studied were divided into four groups to accommodate the different test variables. Pdf a general winding design rule for the polephase modulation ppm induction machine is proposed, and three. Before the motor is put into operation after a long period of storage, you have to measure the winding insulation resistance. These motors run conveyor belts, pumps, fans, and many other applications. The graph below shows an example of the insulation resistance readings on an electric motor. Keeping motor windings dry internet version of this manual created september 2000. Troubleshooting with insulation resistance test instruments. Testing and commissioning procedure for electric motors eep. This can be accomplished by connecting reactors of the proper design across the motor starter contacts so that when the contacts are open the motor remains energized, but at a very.
Test results of motor starter equipment shall be in accordance with. If you are searching for rewinding of one phase motor you can find it here. The megger will help to detect areas of deteriorating insulation where the windings. Before starting maintenance procedures, be positive that. Phase converter calculations can be done with the same procedure as the. The megger insulation tester is essentially a highrange resistance meter ohmmeter with a builtin directcurrent generator.
Design and development of three stator 343 power consumed due to eddy currents, copper losses and poor power factor are considerably reduced 11. Given the sheer number of different motors and winding patterns, the rewinding process can vary greatly. An electric motor is an electrical apparatus that converts electrical activity into automated energy. Motor installation and maintenance instructions gei 56128h.
Most repair shops will use a megger or a ground insulation tester. Learn how to troubleshoot 3 phase induction motor step by step with circuit diagram, figure and important points about induction motor star delta connection. Any other particular features of the motor configuration. Best practice manual electric motors prepared for bureau of energy efficiency, under ministry of power, government of india hall no. The subtests that make up a test procedure shall be performed in the sequence listed. All safety materials and equipment warning signs, barricades, fire extinguisher, etc.
Electric motors are relatively simple mechanical devices, but rewinding them isntin fact, its one project thats usually best left to the professionals. Dc motor fault zone analysis is a vital part of any dc motor maintenance program. The complete guide to electrical insulation testing. How to wind threephase stators selfpaced, interactive training for stators 600 volts or less this valuable interactive training tool is ideal for training your novices. Work permit shall be prepared prior to start any activities. Record initial and corrected values on motor testing record sheet. The ohms reading for each winding must be the same or nearly the same. All values obtained from winding dc resistance test. Identifying unmarked leads of 6lead motors with 1 or 2 windings procedures also help identify type of connection when there is no nameplate continued on page 4 one frequent request of easas technical support staff is for help in identifying unmarked motor leads. Maintenance safe maintenance practices performed by qualified personnel are imperative. The stator is kept in the oven at temperature of 650 degrees fahrenheit for at least 10 hours or until the winding insulation turns to ash. Comprehensive guide to electrical motor rewinding process. Mar 05, 2019 vacuum pressure impregnation vpi utilizes a vacuum pressure tank filled with varnish to fully impregnate motor windings and insulation with resin or varnish.
Ieee std 1122004 revision of ieee std 1121996 ieee standard test procedure for polyphase induction motors and generators sponsor electric. If we found infinity resistance or no continuity in any winding, motor is faulty. If a singlephase motor is single voltage or if either winding is intended for only one voltage, the terminal marking shall be determined as follows. A guide to maintenance practices for small horsepower vering construction control and maintenance, including armature winding. A text book of motor winding guide in urdu urdu books pdf. Measure motor winding and feeder circuit resistance, exciter resistance if synchronous motor and record results, if applicable. When a motor fails, it is often difficult to see why it failed just by looking at it. Stationary part of the motor sometimes referred to as the windings. Tutorial how to rewind electric motor part one youtube. In this instructables i will show you, how to rewind and renovate old electric single phase electric motor.
The megger will help to detect areas of deteriorating insulation where the windings may soon short. Alternating current ac and direct current dc motors employ an insulated, currentcarrying coil essential to their operation. Get motor rewinding procedure pdf file for free from our online library pdf file. Motors are susceptible to the gradual failure of their insulation resistance. However, it generally involves cutting the original. Ieee std 1122004, ieee standard test procedure for polyphase. Remember that the bldc motor is usually connected in wye. In next steps i will show you how to analyse motors winding, disassemble motor, remove bearings, calculate new winding, rewind motor, reassemble it with new bearings and test motor. Pdf the paper unifies previous experiences related to the motor rewinding. An insulation multimeter can be used to check insulation integrity between commutator segments prior to rewinding.
The test results summarized below show no significant change in the efficiency of motors rewound using good practice repair procedures within the range of accuracy of the ieee 112b test method, and that in several cases efficiency actually. This magnetic field continuously pulsates across the air gap and into. This article introduces a set of procedures for identifying unmarked leads of 6. Rtd circuits shall be in accordance with system design intent and machine protection device. Check for any loose or faulty electrical connections within the control panel.
Verify that the motor space heater when installed is energized when motor is deenergized. Routine test of three phase induction motor vishant naik1, saurabh k singh2, sahil chawhan3. The windings are marked with tags u1 and u2, v1 and v2, w1 and w2. Perform and evaluate an insulation resistance test in accordance with project test procedures. Remember that the three phases have identical windings or. For a bldc motor apply the ac voltage to one pair of the three wires. Department of energys office of industrial technologies oit with input from trade associations, consulting companies, manufacturers, nonprofit corporations, and others. Connect a megohmmeter to measure the resistance of each winding lead to ground. Pdf winding design, modeling, and control for polephase. To obtain on load current and its power factor angle. Page 1 of 2 how to check the windings of a 3phase ac motor the rotor of a squirrelcage motor there are several different ac motor types, each one with different operating and mechanical characteristics. Apr 14, 2018 this video content about the information of 24 slot, 4 pole, 1500 rpm, 3 phase induction motor winding design. Practical information and data covering winding and reconnectig procedure for direct and alternating current machines, compiled for electrical men responsible for the operation and repair of motors and generators in industrial plants and for repairmen and armature winders in electrical repair shops.
At dreisilker, we preheat our windings, place the windings in our 10 ft. How to test three phase ac motors learning electrical. Isbn 07389785 ss95211 no part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher. Motor parameters these are the motor parameters that are needed. Power factor of a motor at full load varies between 0. And also you can use lcr to measure the inductances of each winding. Mar 28, 2018 in this video you will find out how to test 3phase induction motor. Ac motor winding resistance test check the motor winding resistance or ohms reading using a multimeter or ohmmeter for phase to phase terminal u to v,v to w,w to u. Electrical motor rewinding procedure steps before the commencement of rewinding it is important to note the nameplate data and the connection of winding pattern of the machine. Dip and bake epoxy varnishing, trickle varnishing, vacuum pressure impregnation, and.
Measure resistance between stator windings in ohms. The copper is a conduit for the stator winding current. These values are used for the calculation of temperature rise. I always megger a 3 phase 480v motor phase to ground, but i am wondering if meggering phase to phase can tell me something about the state of the winding insulation as well, and what kind of a reading i would be looking for considering the windings are shorted together. Rewinding motors with no specific controls on stripping and rewind procedures. At all times remember te follow correct safety procedures during the performance activity. How to test a 3 phase motor windings with an ohmmeter.
If we found continuity between earth and winding, motor is faulty. Jan 04, 2017 electrical motor rewinding procedure steps before the commencement of rewinding it is important to note the nameplate data and the connection of winding pattern of the machine. Threephase dualvoltage motor insulation resistance testing. Carefully examine the interior of the motor for loose objects such as, nuts and bolts. This insulation protects the windings from contamination, shorting electrically, and also make the windings more mechanically rigid. With the motor at normal operating temperature, the vibration velocity shall not exceed 2. This method produces heat in the winding conductor where it is most effective in driving out moisture. In this insctructables, i am going to make step forward. For good insulation, the resistance usually reads in the megohm range. Minimum resistance of motor winding insulation is 5 meg ohms or the calculated minimum, which ever. Tutorial how to rewind electric motor part one wet head pump repair.
The traditional method for motor rewinding involves removing the old coil, winding a new coil and varnishing. Nov 23, 2015 learn how to troubleshoot 3 phase induction motor step by step with circuit diagram, figure and important points about induction motor star delta connection. Visual inspection and electrical testing of the armature and fields give the maintenance personnel an understanding of the condition of the motor. The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. Sandblasting is process where sand hits surface of workpiece with very high speed. The most common failure mode of a 3 phase ac motor is burnt winding or shorted winding leading to the damage of the motor. Ieee std 1122004, ieee standard test procedure for. When a bad motor winding cannot be found by a physical inspection, many times an ohmmeter may show that there is a defective winding. Do not lift both the motor and driven equipment with the motor lifting means. Winding failures on large ac motors 100 hp and up have been reported in increasing numbers. Check electrical condition of insulation on power cables and on all phases of the motor in meg ohms.
If the motor is not put into operation immediately upon arrival, it is important to protect it against external factors like moisture, high temperature and impurities in order to avoid damage to the insulation. Coils are used as components of circuits, and to provide the magnetic field of motors, transformers, and generators, and in the manufacture of loudspeakers and microphones. Measuring motor parameters control technology corp. Check voltage supply between all phases of the electrical control panel. Jan 31, 2015 help diploma of associate engineering d. Electric motor repair, model repair specifications for low voltage motors, and motor repair tech brief were produced by the u. The measured resistance values of motor field windings, exciterstator windings, exciterrotor.
There are four types of varnishing methods that we will describe below. The effect of repairrewinding on motor efficiency iecex. Electric motor testing electrom instruments brochures. At a, the insulation resistance decreases due to aging and dust accumulation. Motors cannot be repaired, nor can they maintain performance and efficiency. The shape and dimensions of a winding are designed to fulfill the particular purpose. After a motor is rewound, the windings must be further insulated with resin or varnish. Page 1 of 2 how to check the windings of a 3phase ac motor. May i request you to give a procedure in measuring the inductances. Electric motor repair, model repair specifications for low voltage motors, and. Inspection and test procedures for rotating machinery.
Since there are several types of electrical motors available in the industry the method which use for rewinding one type of motor is not same as others. A motor placed in storage may or may not work, regardless of its physical appearance. The efficiency of an induction motors ranges between 0. Threephase dualvoltage motor insulation resistance testing threephase dualvoltage motors are used for most daytoday operations in todays industrial plants. Design and development of three stator winding induction motor. Identifying unmarked leads of 6lead motors with 1 or 2. For a dc motor, apply the ac voltage to the armature winding. A general mathematical formulation for winding layout.
This installation and maintenance manual has been written to assist the user with proper procedures when handling, installing, operating and maintaining the equipment. Thus some other procedure must be used to measure the current or torque and velocity. Threephase currents flowing in the stator windings leads establish a rotating magnetic field in the air gap. Well learn how to identify windings, check windings. Electrom motor testers and winding analyzers are sold worldwide to motor repair companies. Iec 6003421, table 2 stator winding resistance measurement at ambient temp. In electrical engineering, coil winding is the manufacture of electromagnetic coils. Winding design, modeling, and control for polephase modulation induction motors article pdf available in ieee transactions on magnetics 492. Another interesting winding design method, based on tables, has. During operation these materials may be subject to electrical, thermal and mechanical stresses and must be capable to endure the same and possess the following, electrical stresses. In this video you will find out how to test 3phase induction motor.
To measure the motor inductance use a low voltage ac source to the motor winding. Often it is required to test the winding of the 3 phase windings with the aid of a multimeter or ohmmeter to determine whether the motor is still good or burnt or shorted. How to check the windings of a 3phase ac motor with an ohmmeter. General procedure double layer simplex lap winding double.
How different burnout temperatures affect stator core. Implementing a predictive maintenance program takes a. Model repair specifications for low voltage induction motors. Before performing any motor maintenance procedure, be sure that the equipment connected to the motor.
Read online now motor rewinding procedure ebook pdf at our library. The motor for any application should not be oversized or undersized. Improves power factor of the motor resulting in lesser current drawn and reduced cable losses key points to remember. There are various methods suggested to improve efficiency and power factor of an induction motor. How to check the windings of a 3phase ac motor with an. Old coils are removed by heating the stationary part of the motor stator in an oven.
Well learn how to identify windings, check windings resistance and insulation resistance. The key objectives of winding treatment are to make the winder knowledgeable and proficient in the equipment and materials to varnish treat and cure windings. If the motor has been in storage more than six month or has been subjected to adverse moisture conditions, it is best to check the insulation resistance of the stator winding with a. Once these details are recorded the damaged windings are carefully removed and check for the details such as no of turns per slots, the gauge of the conductor. In the running configuration, the windings are joined with metal jumpers.
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