Threephase dualvoltage motor insulation resistance testing. If the turn insulation fails in a formwound stator winding, the motor will likely fail in a few minutes. All books are in clear copy here, and all files are secure so dont worry about it. Ieee standard 432000, recommended practice for testing insulation resistance of rotating machines, recommends the insulation test voltage to apply, based on winding rating, and minimum acceptable values for electric motor windings. Evaluation ofmarkets andefficiency offractionalpolyphase motors.
Jul 17, 2017 if the winding s insulation wears away near the motor s case, the barewire winding shorts to ground. Read online iec standards for variable speed drives and motor winding. We highly recommend using a qualified, experienced vendor like tigertek for your spindle motor. How to properly test ac stator and wound rotor windings. Understanding insulation resistance testing pdf 0712. Checking spindle motor windings how to check for bad windings in a spindle motor to check your spindle motor for bad windings, you can use several different methods. Winding analysis can also be utilized as a powerful troubleshooting tool. To do this for delta connected 9lead motors, remove the wirenuts from 4 and 7, 5 and 8, and 6 and 9. Electric motor testing explained the electricity forum. Using a phase rotation meter on your newly bought motor or pump can ensure new or refurbished motors are good before being installed, or can monitor existing motor health for developing problems. However, if the motor design has external brush holders, you can unscrew the brush caps and remove the brushes. Industrial motor testers electric motor winding test. Motors are susceptible to the gradual failure of their insulation resistance.
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. The purpose of this manual is to provide direction and to the greatest extent possible, to assure a safe work environment for all electrical employees. If you open the single phase motor, you will find out that your motor have two types of winding in which one is made from thick wire gauge and one thin. Get motor rewinding procedure pdf file for free from our online library pdf file. Threephase dualvoltage motor insulation resistance testing threephase dualvoltage motors are used for most daytoday operations in todays industrial plants. Mar 29, 2019 check that the windings are not open or blown. Low voltage tests on formwound stators, such as inductance or inductive impedance tests, can detect if the turn insulation is shorted, but not if it is weakened.
If the computer simply by connecting to the detects a weakness in the insulation, preprogrammed motor, the test is interrupted, the operator is ensuring a higher degree of alerted, and all test parameters at automatic or manual reliability in testing procedures. The meter should not show an open or a short when a winding leg is measured. Table 2 provides the test results for the 30 kw motor when tested at 50 and at 60 hz. Figure 4typical record of insulation resistance of a mill motor. The slip ringsbrushes allow external resistors to be connected in series with the winding. This means that the motor is an essential part of any pump. Electrical insulation for hightemperature, cryogenic, and. Depending upon brush size, this may allow access to the commutator without removing the armature from the motor. Technicians should perform a series of tests on an electric motor during routine preventive maintenance or before replacing it. Motor testing equipment newer more contemporary instruments make testing even easier. Review of electrical tests to assess motor windings. A defective winding may be classified as an open winding or a shorted winding. But smart companies understands is that what this means for maintenance programs is billions of dollars of lost revenue through increased motor repair costs, downtime, and waste in industrial and commercial companies.
Testing the state of the windings by the winding resistance and insulation. Lindstrom, thermal model of a permanentmagnet motor for a hybrid electric vehicle, department of electric power engineering, chalmers university of technology, goteborg, sweden, 1999. How to check a motor armature for damaged windings groschopp. But this identification can only be done by disassembling the motor. Read online now motor rewinding procedure ebook pdf at our library. Easa aemt study of motor repair impact on efficiency.
Curve b shows same values corrected to 20c see page 22, giving a definite downward trend toward an unsafe condition. The tester analyzes the electric motor fast and reliably. Understanding insulation resistance testing aemc instruments. Fluke 1507 motor insulation and low ohm testing duration. A test voltage is applied for a fixed period of time, usually. Methods of rewinding testing the new winding testing of armature. The display will be zero if the winding is grounded. Motor winding phase testers a phase rotation meter can help detect motor faults not detectable by other instruments. The comparative environmental impacts of motor rewinding vs. Consult the motor schematic or a diagram of the motor s windings and use the meter to measure the resistance of the windings. The rotor winding terminals are connected to three slip rings which turn with the rotor. Automated testing with the push of a button makes motor testing easy and available for personnel who are not experts, and who do not use a motor tester all the time. Aug 06, 2017 fluke 1507 motor insulation and low ohm testing duration.
The following series of repair documentsthe service center evaluation. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors. The voltage stress placed on a motors insulation due to high peak voltages and shortrise times that occur when the motor is driven by a vfd. Evaluating and measuring the amps and voltage per phase when a motor is running, as well as rotor bar tests. The thick wire gauge winding is main winding and thin wire gauge winding is starting winding. The measurement of the winding resistance is commonly the first test performed. All testing used the losssegregation method at no load and full load, which allowed for detailed analysis. The itig ii winding analyzer will take the guess work out of your maintenance processes when it comes to the testing of insulation systems. The baker awaiv is the result of more than 45 years of experience in the design and manufacture of motor winding testers. To effectively test the motor, you must disconnect the field coils where possible. Thus the turn insulation is critical to the life of a motor. Three phase slip ring induction motor a wound rotor or slip ring motor has a 3phase winding, similar to the stator winding.
Download iec standards for variable speed drives and motor winding. For good insulation, the resistance usually reads in the megohm range. After that, the interturn short circuit is the immediate. Nov 01, 2012 to check the condition of the armature windings, the armature will probably have to be removed from the motor. Pdf testing and analysis of induction motor electrical faults.
Understanding insulation resistance testing pdf 0712 technical assistance 800 34391. These motors run conveyor belts, pumps, fans, and many other applications. This prevents testing coiltocoil insulation resistance for all six coils and their combinations. The complete guide to electrical insulation testing. Measuringefficiency it is important to understand motor efficiency and how it is determined in order to interpret the results ofthe testing this report initially, efficiency in these motors will be.
When the observed temperature rise of the motor winding does not vary more than 2f. Ieee standards documents are developed within the ieee societies and the standards. The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. Ieee std 1122004, ieee standard test procedure for polyphase. Electric motor testing is usuallly the first thing to be sacrificed when cutting back on operational expenses. Each winding leg should have some small resistance reading. Troubleshooting with insulation resistance test instruments. Improving motor and drive system performance energy. Winding design, modeling, and control for polephase modulation induction motors article pdf available in ieee transactions on magnetics 492. Electrical and motor machine shop safety procedures. As always, make sure to disconnect all power from machine before doing anything. Offline tests that are done during a shutdown insulation resistance, motor circuit analysis, surge test, hipot test, growler, visual inspection. The effect of repairrewinding on motor efficiency easa.
Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. This article describes how the following standards address these questions. Electrical and motor machine 61 electrical and motor machine shop safety procedures this section has been formulated to set guidelines for all electrical work performed by this department. Use the schematic and take readings of all of the windings. If, during the procedure for identifying motor terminals, the ohmmeter displays a blank readout during any test, there is probably a defective winding. Checking spindle motor windings how to spot bad windings in.
Figure 3typical scale on the megger insulation tester. Electrical insulation for hightemperature, cryogenic, and other harsh environments hightemperature motor windings for downhole pumps used in geothermal energy production matthew hooker composite technology development, inc. There is much discussion in the industry about how to properly electrically test ac stator and wound rotor windings. Reverse side of card at right is used to record the test data.
Insulation resistance testing is performed when troubleshooting electric motors and related equipment. Consult the motor schematic or a diagram of the motors windings and use the meter to measure the resistance of the windings. Review of electrical tests to assess motor windings format. The megger insulation tester is essentially a highrange resistance meter ohmmeter with a builtin directcurrent generator. Oftentimes, acceptance testing of motors is specified. Pdf stator winding tests are usually performed to detect problems in the electrical insulation. These tests can be conducted with the help of an advanced winding analyzer awaiv and a baker d65r, depending upon motor type.
Many simple across the line singlephase and 3phase motors used in household appliances and industry respectively can be checked simply by changing the range of the ohm meter to the lowest offered r x 1, zeroing the meter again, and measuring the resistance between the leads of the motor. Ieee std 1122004 revision of ieee std 1121996 ieee standard test procedure for polyphase induction motors and generators sponsor electric. Topics include test voltage, procedure, frequency and when to perform the various tests. Model repair specifications for low voltage induction motors. For instance, test equipment such as flukes 438ii power quality and motor analyzer uses algorithms to analyze not only threephase power quality but also torque, efficiency and speed to determine system performance and detect overloaded conditions, eliminating the need for motor load sensors. May 18, 2010 hightemperature tools and drilling this presentation does not contain any proprietary. All baker awaiv testers, which include 2, 4, 6 and 12 kv models, are fully compliant with industrystandard ieee motor test recommendations. Pdf winding design, modeling, and control for polephase. Motorguard is an automatic insulation resistance tester that monitors and protects criticalduty motors. This standard provides the basic test procedure for evaluating the.
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