Inspection and test procedures for rotating machinery. Ieee std 1122004, ieee standard test procedure for. Model repair specifications for low voltage induction motors. Winding ground faults in large synchronous hydrogenerators and motors, by. Motor faults motor protection overview ge grid solutions. Maughan, president maughan generator consultants schenectady, ny, usa abstract. The core is constructed in the form of laminations and the material used for the same is either magnetic iron or steel alloy. Electric motor construction of induction motors britannica. Those common questions can be answered by checking the stator core condition. Turbine field rotor repair and rebuilding including retaining ring inspections, rotor field cleaning, testing, rewind and recondition. Method of evaluating loss distributions within the electric motor for different operating conditions in collaboration with university of wisconsin madison development of stator thermal model validated against published data parameter sensitivity study of thermal design factors for motor stator.
The ultimate solution for stator core and lamination repair. Another integral part of the stator is the stator core which is supposed by the stator frame. Ieee std 1122004 revision of ieee std 1121996 ieee standard test procedure for polyphase induction motors and generators sponsor electric. Insulcore solutions electric motor core repair msc. Tutorial how to rewind electric motor part one youtube. How capacitor discharge ignition cdi system works and. For over 20 years ricky stator has been rewinding modifying and repairing stators for the powersports industry. When, during the course of a repair, a motor or generator stator is found to have.
The stator core is fixated inside the motor house and is made of laminated electrical steel sheets. Repair, evaluation, maintenance, and rehabilitation remr research program identify the problem area under. A capacitor discharge ignition consists of several parts and is integrated with the ignition system of a vehicle. Watch the entire electric motor rewind process with this video from the gibbons engineering group workshop in essex. In this instructables i will show you, how to rewind and renovate old electric single phase electric motor. Harley and yao duan georgia institute of technology november, 2009. The laminations are insulated from each other usually by a varnish layer. Easa aemt study of motor repair impact on efficiency. Here are tips on how to find the problem, fix the rotor, and get the motor running again. Mmf drop along stator teeth, rotor teeth, stator core and rotor core. A new method for stator core repair reduces core losses and.
Ac motor repair report form page 39 appendix f mechanical inspection for motors as completed page 40. Diagnostics of rotor and stator problems in industrial. Coils of insulated wires are inserted into these slots. Recommended practice for the repair of rotating electrical apparatus ansieasa ar1002010 was published recently by the electrical apparatus service association easa. A new method for stator core repair reduces core losses and repair time abstract. How different burnout temperatures affect stator core losses. Plant engineering a systematic approach to ac motor repair. A systematic approach to ac motor repair ansieasa ar100 provides best practices for mechanical repair, electrical repair including rewinding, and testing that help apparatus rebuilders maintain or enhance the performance, reliability, and energy efficiency of ac and dc motors and generators.
An inductive rotor is constructed by laminating iron disks together to form the central core of the rotor. Many sections are mainly applicable to the lvmv induction motor equipment and many others are applicable to either synchronous or dc motors. 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. This way we can evaluate your stator and make sure it is repairable before you send. Pdf electric motor repair for low voltage induction motors in pwm. Prior to the thermographic survey, the damaged sections of the core were repaired and. Among other actions, the procedures followed by highquality shops include conducting a stator core test before and after winding removal, as well as confirming that the core has not been damaged during the repair process. Technical bulletin core loss testing theory ird balancing. Some sections may explain explicitly between the three. The stator core is made up of many thin metal sheets,called laminations. High power ac motors are typically inductive in design. This shop order number should be listed on the repair invoice.
The foremost parts of a cdi include the stator, charging coil, hall sensor, flywheel and the timing mark. As a result, the motor rotates in the direction of the resultant torque. An outside repair firm was hired by the customer to conduct all necessary repairs on this stator. Now, a 500 hp stator core with a known watt loss can be compared to that of a 5 hp stator. A core loss test is to be carried out on every stator to be rewound.
How to test and assess stator core condition using a loop. Fletcher moorland ltd electric motor repair specification. The effect of repairrewinding on motor efficiency easa. The steel laminations used in the stator core of electric motors and generators are electrically insulated from one another to reduce eddycurrent losses. Groundwall insulation failure usually triggers a ground fault relay, taking the motor or generator offline. Getting the rotor back up and running machine design. Actually you can see the combined diagram of both the stator core as well as the stator frame first of the three diagrams above. Pool pump repair video series by the pump guys joseph and robert from the website. Conduct a stator core test before and after winding removal. Stator the stator is made up of several thin laminations of aluminum or cast iron.
Pdf it is necessary to present a motor repair specification for the repair of. This checklist incorporates all range of motors equipment. It also will explain how to analyze the results, providing information about the associated equipment, tips for repairing core damage and explain other alternatives for stator core. The stator is the outer body of the motor which houses the driven windings on an iron core. Motor driven equipment often provide core capabilities essential to business success and to safety of equipment and. This particular stator had suffered a failure resulting in the burning out of a series of iron packs located throughout the turbine side of the stator. This will assure that the core has not been damaged during repair. Visually inspect for signs of axial and radial movement.
This presentation will discuss how to perform a stator core test using a loop test. Skin effect may not be neglected in linestart motors when assessing the starting, or breakdown torque. Pdf evaluation of induction warming stator cores for coil removal. Rotor is usually made as squirrelcage, and it is inserted in stators hole. To rewind an electric motor, remove the motors outer housing and use your hands to pull the armature out of the stator. 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. Traditional design of cage rotor induction motors ronald g. In addition to conventional squirrel cage rotor testing methods such as the growler test, also covered will be techniques such as the use of a core loss tester, high current excitation, and spectrum analysis of vibration. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. Record stator current, stator voltage, and field current for the complete acceleration period.
For a long service life, the groundwall must meet the. Since inception, lexsco has performed core loss tests in a variety motor repair shop environments. Navsea motor repair manual, identified that these methods. A new edition of the only american national standard for repair of motors and generators ansieasa ar1002010. Electric motor repair equipment whitelegg machines.
A second goal was to identify procedures that degrade, help maintain or even improve the efficiency of rewound motors and prepare a good practice guide to maintain motor efficiency part 2. In a singlespeed threephase motor design, the standard stator has three windings, while a singlephase motor typically has two windings. They are punched and clamped together to form a hollow cylinder stator core with slots as shown in figure 1. The rotor body is the rotating part of the motor and is made of a steel core with aluminium windings. Lamination is necessary since a voltage is induced along the axial length of the steel as well as in the stator conductors. Getting to the core of your generator stator problems. This article presents a basic explanation of electric motor construction and. The tests shall be done at a flux density of 85,000. Inplant service for turbine rotors including rso testing, insulation resistance testing, impedance testing and shutdown work. Core loss testing and hotspot testing are vital when it comes to determining the condition of the ac induction motor. Electric motor electric motor construction of induction motors. A new method for stator core repair reduces core losses. When a bearing failure results in friction between the rotor and stator, or a ground fault occurs.
Thus the stator groundwall insulation is critical to the proper operation of a motor or generator. They are insulated with resinrich glass and mica paper tapes. Whitelegg now offer an unrivalled range of equipment to the electric motor repair industry. Ger4212 ge generator rotor design, operational issues. Easa aemt study of motor repair impact on efficiency thomas h. Past, present and future john petro petro and associates consultants. Sources of stress in the machine that lead to stator winding deterioration. The stator core has slots that are filled with copper windings. The stator frame consists of laminations of silicon steel, usually with a thickness of about 0. Introduction three phase motors can be classified into two types. The insul core solutions process provides the ultimate opportunity to potentially restore the core plate without dismantling the core, saving labor, eliminating the chance of unsatisfactory restack results and the possibility of scrapping an expensive piece of electrical equipment.
The steel laminations used in the stator core of electric motors and generators are. Abstract the steel laminations used in the stator core of electric motors and. The stator core is made up of a stack of round prepunched laminations pressed into a frame, which may be made of. The coils are preformed and cured before insertion into the stator slots. The stator core is built of sheetsteel laminations that are supported in a frame. Evaluate the impact that physical damage to the stator core has on efficiency. A final objective was to attempt to correlate results obtained with the running core loss test and static. We use only the best materials available and can rewind a wide range of stators. For large motors, the practice is to wind the stator with formed coils figure 9.