Written for professionals who work in electric motors, this covers updated traction applications, the latest on solidstate motor drive controllers, electrical and mechanical parameters, specifications, shapes, performance, protection, and more. An induction motor also known as an asynchronous motor is a commonly used ac electric 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. Slipring induction motor also known as rotor resistance start motor. As energy costs rise, more emphasis is being placed on determining the health of large inductive motors. As shown below, the indicated terminal matrix blue lines shows the way the windings of a 3 phase motor should be tested with an ohmmeter. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them. Testing and commissioning procedure for electric motors eep. 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.
Apply rated voltage and frequency with no mechanical load. The high temperature superconducting bulk can be used as the rotor of an ac motor. In this test, a rated, balanced ac voltage at a rated frequency is applied to the stator while it is running at no load. Motor vibration shall be measured in a triaxial direction, i. In this test we use megger in megger generally two components are present dc generator and. Home category electrical engineering mcq questions and answers 3 phase induction motors 1 the frequency of the induced emf in an induction motor is a. Induction motor is an energy conversion device that converts electrical energy into useful rotational kinetic energy, it is an application of the faradays law of induction. This paper aims to represent routine test performing in three phase induction motor. Instructions for conducting and reporting the more generally applicable and acceptable tests of polyphase induction motors and generators are covered. Ieee standard test procedure for polyphase induction motors and generators 3 park avenue, new york, ny 100165997, usa ieee power engineering society sponsored by the electric machinery committee 4 november 2004 print. The rotor of an induction motor is like the secondary winding of a transformer, with the motor stator being the primary. The squirrel cage induction motor was designed for an extended service life under very demanding conditions.
If the meter readout indicates 0 resistance, the capacitor is shorted out and needs to be replaced. Diagnostics of rotor and stator problems in industrial. We look at different motor types, methods for testing them, which megohmmeters to use for which types of testing, and questions to consider when setting up your own insulation testing program. All safety materials and equipment warning signs, barricades, fire extinguisher, etc. The set up for no load test of induction motor is shown in the figure. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. Slipring induction motor connection and testing people education online. The no load test of 3 phase induction motor is performed on induction motor when it is running without load. Onsite testing is routinely implemented once or twice a year or during scheduled outages. This test tells us the magnitude of constant losses occurring in the motor. Ac motor testing performed with pdma mce offline tester resistive imbalance during this test a dc voltage is applied to the motor.
When a three phase induction motor connected to a single phase power supply using the steinmetz connection operates in a practical noload condition, not all windings consume active power. Since the vast majority of electrical machines are applied at electrical power frequencies, it is to be expected that the testing procedures are based on a fixed frequency power supply, usually 50 or 60 hz. The state of surge testing on induction motors introduction surge testing of motor coils has been an industry practice since j. The inspection and test plan for induction motor article provides you information about induction motor test and induction motor inspection in manufacturing shop. For single phase motors, the expected voltage is about 230v or 208v depending whether you are using the uk or america voltage system. Motor current monitoring and analysis mcsa is a straight forward tool to diagnosing problems with large inductive motors.
The three resistance readings of a threephase induction motor are compared and calculated to obtain the resistive imbalance. The testing of standard motors is described in iec 600342. Induction motor testing and evaluation summary as energy costs rise, more emphasis is being placed on determining the health of large inductive motors. 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.
The complete guide to electrical insulation testing. Here we are giving you only overview on 3 phases induction motor. Written for professionals who work in electric motors, this covers updated traction applications, the latest on solidstate motordrive controllers, electrical and mechanical parameters, specifications, shapes, performance, protection, and more. Jul 06, 2016 motor testing equipment newer more contemporary instruments make testing even easier. Rewinding of motors pdf the information in this report and the good practice guide to maintain motor efficiency part 2 was. 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. This is easiest to visualize at motor startup, when the rotor. As discussed in chapter 16, the squirrel cage comprises the bars and. The rotor of a conventional squirrel cage induction motor was replaced with cylinder type ybco bulk. Testing can be conducted without interrupting the normal operation of the motor, and in fact should be performed when the motor is under a minimum of 70% load. An electric motor converts electrical energy to mechanical torque using an interaction of. Remove one of the wires from the capacitor to test the resistance of the start induction run motor. The singlephase induction motor is much the same in construction as the threephase motor.
The main difference between the standards is the way in which the fifth loss component stray loss p stray, the additional load losses, is treated. Model repair specifications for low voltage induction motors. Uses same test instrument setup as lockedrotor test. 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. For motors falling outside this description, the more comprehensive model specifications below are recommended. The locked rotor test is made at 15 hz to minimize the errors due to saturation and skin effects.
The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. The load test on induction motor is performed to compute its complete performance i. Review of testing methods for fullload temperature rise testing of induction machines. Ieee std 1122004, ieee standard test procedure for. To determine whether a 3 phase motor is still good or has gone bad, a simple ohmmeter test across the windings of the motor will reveal its true state of health. Threephase dualvoltage motor insulation resistance testing. How to test a 3 phase motor windings with an ohmmeter.
Testing practices for synchronous and induction machines have been developed over the years and documented in detail in ieee standards 1,2. The no load test on an induction motor is conducted to measure the rotational losses of the motor and to determine some of its equivalent circuit parameters. The draft inspection and test plan provided as well. In the following paragraphs two different methods of. The machine is started in the usual way and runs unloaded from normal voltage mains. Work permit shall be prepared prior to start any activities. Guide for testing three phase induction motors first revision 1 scope this guide prescribes methods for conducting and reporting tests for three phase induction motor. Set your dmm to the ohms function and touch the probes to the terminals on the capacitor. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to. Static or offline testing is performed while the motor is not running and can be executed on site, in inventory, or in a motor repair facility.
Sep 15, 2019 loss distribution in an induction motor. Record all nameplate information for the induction motor. That is, the motor shall not be dismantled to remove sealing elements. However, should the motor require service, this manual includes a section that assists the.
In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding. Testing of increased safety ht induction motor for. Current, voltage and power are measured at the motor input. It should be noted that the scope of motor testing depends upon the motor type and size, this being indicated on the inspection forms. Aug 30, 2018 remove one of the wires from the capacitor to test the resistance of the start induction run motor. Ac motors are required in many modern adjustablespeed drives. Induction machines are considered relatively reliable and robust due to their simple design and welldeveloped manufacturing technology.
Aug 05, 2017 in this we check induction motor by megohmeter. Model repair specifications for low voltage induction motors these model repair specifications are intended to cover routine repair and rewind of lowvoltage randomwound threephase ac squirrel cage induction motors. Motor current signature analysis mcsa is a proven and accepted method for determining the condition of a motor s current carrying components. Draw the approximate equivalent circuit for the motor lockrotor noload dc test v line 36. Initial and date the results of the following instructions and tests on attachments to this procedure. This is easiest to visualize at motor startup, when the rotor is not yet turning. It utilizes a low voltage, high frequency signal to measure the inductance l reading for each of the stator windings in a threephase ac induction motor. Sealing elements that can only be removed by dismantling the motor shall be left in place. Rylander published a high frequency voltage test for insulation of rotating electrical apparatus in transactions of the aiee, in february of 1926. Horizontal squirrel cage mediumvoltage induction motor. From this voltage the actual resistances of the windings are measured.
Noload test balanced voltages are applied to the stator terminals at the rated frequency with the rotor uncoupled from any mechanical load. Testing motors with motor circuit evaluation detecting rotor defects with mce testing technology is one of the newest forms of rotor testing in todays market. The losses in the noload test are those due to core losses, winding. For good insulation, the resistance usually reads in the megohm range. You should also make a dc measurement of stator winding linetoline resistance using a dmm. 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. Determine the motor parameters and the total core, friction and windage losses. Although an induction motor is highly symmetrical, it may still have a detectable sig. The purpose of these tests is to estimate the performance characteristics of the induction motor. During this test, the motor is operated at rated voltage. Testing of a squirrel cage rotor requires some understanding of how the rotor functions. If the capacitor is good, the readout will read a very.
Three phase induction motor model design and performance analysis in ansys rmxprt. With a multimeter, measure the resistance between motor frame body and earth. Naturally, the bearing temperature will increase by passing the time. Along with preliminary tests, these tests are also done on motor. No load test of induction motor your electrical guide. The rotor of an induction motor can be a squirrel cage rotor or wound.
This paper presents the fabrication and test results of a ac motor with hts bulk rotor. In this test we use megger in megger generally two components are present dc generator and ohm meter dc generator generate high voltage such as. The megger insulation tester is essentially a highrange resistance meter ohmmeter with a builtin directcurrent generator. The induction motor shall run at the rated voltage and frequency, and each bearing temperature is measured periodically. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity to a circular animal exercise wheel. How to test and check single phase electric motors. Induction motor is one of the most important motor used in industrial applications. Static testing measures and evaluates the integrity of the insulation system. Squirrel cage wound rotor with slip rings the rotating magnetic field the basic idea of an electric motor is to generate two magnetic fields. Slipring induction motor connection and testing youtube. The temperature rise should not be bo more than specified value in the induction motor testing procedure or motor datasheet. The motor is mounted in a test rig that allows one to control the torque applied to the motor shaft and to measure both rpm and torque. Recommended interpretation of iec 6003421 external contact seals at the drive shaft extension ends shall be removed prior to testing.
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