Further troubleshooting maybe required power supply test for three phase motors, the expected voltage for a 230400v system is 230v phase to neutral and 400v between each of the three phase supply lines. It is better to carry out an initial test at 30 or 50 volts and if the. This troubleshooting guide can also be applied to other types of three phase induction motors. If the motor is completely unresponsive, no ac humming or false. Test inter phase resistance by disconnecting the leads from each terminal with a flathead screwdriver, then touch any two terminals with the two probes. Once you have tested a few 3 phase motors, the process will come easily. Diagnostics of rotor and stator problems in industrial induction motors. Deviations from rated fla could signify problems with the motor under test. There are basically 4 problems that the motor windings can suffer from. Following tests are carried out on three phase induction motor to check the.
Before troubleshooting the 3 phase induction motor, we must have to know about the 3 phase induction motor, star delta starter and its connection diagram. A typical 3 phase squirrelcage motor has six connection leads in the electrical connection box for the three coils. Telecommunication engineering, southwest jiaotong university, china, 2005. For single phase motor testing we apply generally three test ntinuty test 2. Three phase motors, ac motors, insulation resistance. Record all nameplate information for the induction motor. Point a represents the motor insulation condition when the motor was placed in service. In order to test a 3 phase motor further, you will have to conduct the following tests to find out if your motor is good or bad. Troubleshooting with insulation resistance test instruments. Installation and maintenance threephase induction motors. Threephase dualvoltage motor insulation resistance testing. This article describes ac electrical motor troubleshooting.
This is a brief course intended to acquaint you with basic electric motor troubleshooting and testing. Set your dmm to the ohms function and touch the probes to the terminals on the capacitor. For a three phase motor, insulation resistance is usually measured between each motor winding or phase and between each motor phase and motor frame earth using an insulation tester or megger. Therefore, learn about these phenomena, find out the cause, and then troubleshoot it. One single phase wattmeter plus miscellaneous apparatus as needed. Here we are giving you only overview on 3 phases induction motor. Resistance tests on resistance temperature detector rtd circuits. Mar 07, 2018 also the testing of capacitor of 1 phase motor and main common problems of motor with multi meter with complete troubleshooting in urdu hindi. Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors.
Aug 30, 2018 remove one of the wires from the capacitor to test the resistance of the start induction run motor. The windings all three in a threephase motor should read low but not zero ohms. If you find a phase toground short, a motor shop may be able to do an inplace repair for a large motor. By using different technique of testing of induction motor along with standard vibration analysis, voltage monitoring, and temperature monitoring provides a complete diagnostic perspective of motor health and condition, power consumption, and overall efficiency. The basic idea of an electric motor is to generate two magnetic fields. Even though a fault in your motor can be found out with the help of a multimeter, still becoming doubly sure really helps. The windings consist of three sets of coils separated by 120 degrees electrical. The trick is knowing which leads to hold on to and which wires make no difference at all. The drive manufacturer will normally specify the correct cable distance.
Oct 27, 2008 3 phase alternating current motor troubleshooting. Actually voltage or current unbalance will produce too much heat thus damaging the motors. Threephase dualvoltage motor insulation resistance testing threephase dualvoltage motors are used for most daytoday operations in todays industrial plants. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity. Refer back to this diagram as the operational requirements of the singlephase motor are discussed. Jul 06, 2016 motor testing equipment newer more contemporary instruments make testing even easier. Problems and premature failures often indicate input power system troubles, poor or deteriorating mechanical installations, or malfunctions in the driven machinery.
These motors run conveyor belts, pumps, fans, and many other applications. How to test single phase motor windings, capacitor, problems. For this motors, we require three phase power supply. Mar 29, 2019 check that the windings are not open or blown. Another possibility is that the driven load is jammed, binding or mismatched. Motordoc llc provides electrical machinery, electrical reliability and industrialcommercial consulting and training as well as the first continuous monitoring electrical and current signature analysis system and esa data collection systems. Instructions for threephase induction motor worldwide electric. The singlephase induction motor is much the same in construction as the threephase motor. If the meter readout indicates 0 resistance, the capacitor is shorted out and needs to be replaced. For instance, test equipment such as flukes 438ii power quality and motor analyzer uses algorithms to analyze not only three phase power quality but also torque, efficiency and speed to determine system performance and detect overloaded conditions. For maximum motor life, the cause of overheating should be identified and eliminated. Sometimes the trouble lies within the power supply, including branch circuit conductors or motor controller. How to test a 3 phase motor is discussed in this article.
If you find a phase on phase short, the motor needs evaluation for a rewind or for replacement. It may be too small or have the wrong starting torque characteristics for the load. Check the reason for the unbalanced three phase power supply, if it is. The principle of rotating type phase sequence indicator is like that phase motor. Three phase induction motor, motor current signature ana lysis mcsa, zsvc, fault diagnosis. However, you might end up needing to rewind or replace it. How to test a 3phase motor gone outdoors your adventure. Therefore, motor troubleshooting involves the entire system, not just the. As indicated in the troubleshooting sections, overheating results from a variety of different motor problems. Motor testing equipment newer more contemporary instruments make testing even easier. Set the voltage setting of the insulation resistance tester to 500v. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors. Predictably, this causes a failure at the weak linkin a wound rotor motor this would be by chuck yung senior technical support specialist electrical apparatus service association, inc. Many simple across the line single phase and 3 phase 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.
Three phase dualvoltage motor insulation resistance testing three phase dualvoltage motors are used for most daytoday operations in todays industrial plants. This final thesis will mostly be dedicated to induction motors but also to synchronous permanent magnet and reluctance motors. Also the foundation of pump a foundation of motor pump must be rigid and secure to provide adequate support. Industries of today use three phase motors widely in highpower applications. In the case of three phase ac alternating current operation, the most widely used motor is a 3 phase induction motor, as this type of motor does not require an additional starting device. Nov 23, 2015 before troubleshooting the 3 phase induction motor, we must have to know about the 3 phase induction motor, star delta starter and its connection diagram.
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. The 3phase set of currents, each of equal magnitude and with a phase. 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. Testing and inspection of surge protection devices. If someone works with ac 3 phase motors, then it is important to know how to connect these motors in star and delta connection, and how to detect an electrical problem. By observing a few essential rules, you will ensure problemfree operation for many years. Identifying motor defects through fault zone analysis. Consider the working of a motor for a better understanding of these indicators. For the motor, test the stator winding resistance phase to phase and phase toground. Maintenance and troubleshooting three phase induction motor. Rated linetoline voltage for threephase ac machines, that.
If you have not been trained in how to work safely near live electrical circuits, do not attempt to measure line voltages. There are two types of induction motors, one with wound type rotor, also called slipring motor and another one with squirrelcage rotor. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. By far the most commonly used ac motor is the induction motor.
Vibration testing of motor after it has started running. The basic steps in ascertaining the health of a threephase ac motor are given below. The following is some common faults and troubleshooting method of threephase induction motors for your reference. The rotor will constantly be turning to align its magnetic field with that of the stator field. Point b represents the effects of aging, contamination, etc. You should also make a dc measurement of stator winding linetoline resistance. Testing a 3 phase motor is as simple as holding the leads of a volt ohmmeter. Sep 22, 2017 for single phase motor testing we apply generally three test ntinuty test 2. How to test three phase ac motors learning electrical. This might result in unexpected motor failures when critical services from such motors are required affecting availability of plants. Prakasam and others published testing and analysis of induction motor.
If the motor doesnt rotate in two phase operation, find the reason for phase loss and eliminate it. Pdf testing and analysis of induction motor electrical faults. If the capacitor is good, the readout will read a very. The 3 phase set of currents, each of equal magnitude and with a phase. Motors are susceptible to the gradual failure of their insulation resistance. Jul 01, 2015 when an electric motor fails to start, runs intermittently, runs hot, or continually trips its overcurrent device, there my be a variety of causes. Test results of stator short faults before misalignment adjust. The stator core consists of many layers of laminated steel, which is used as a medium for developing magnetic fields. Nov 27, 2019 an electrical motor is an electromechanical device which converts electrical energy into mechanical energy. How to test a threephase motor with a megger hunker. Dec 30, 2018 testing of induction motor december 30, 2018 february 24, 2012 by electrical4u demand of energy is growing day by day and along with it cost of energy rising abruptly, so now it is necessary that the health of large motors which consumes maximum power should be taken care off. As energy costs rise, more emphasis is being placed on determining the health of large inductive motors. Diagnostics of rotor and stator problems in industrial.