3 phase induction motor troubleshooting pdf errors

The motorspecified voltage must be present on all three phases. One way to reduce the starting current is to start the motor at reduced voltage. However, all three phase motors that run continuously in air conditioning or large freezer systems are susceptible to overheating if there is a voltage imbalance in one of the phases. Lecture 6 three phase induction motors cairo university. This situation often develops when theres an uneven distribution of single phase loads, either from a nearby panel or throughout the premises. This is a routine procedure used when wanting to reverse the direction of a three phase motor. The table below gives the commonly encountered problems in 3 phase squirrel cage. One single phase wattmeter plus miscellaneous apparatus as needed. What are the faults that can occur in a 3phase induction. If the cause of the overheating was not located during steps 1 and 2, proceed. 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. As the current passes through the coils on opposite sides of the stator, a twopole electromagnet is established, creating a twopole motor.

Faults identification in threephase induction motors using support. The model created by rmxprt will then be used as an input for empulse as a basis for performing more detailed analysis and for increasing the accuracy of the performance pre. For the motor, test the stator winding resistance phase to phase and phase toground. These types of motors are known as selfstarting induction motors. Induction motor solved problems examples, torque, starting torque, power developed. The very first thing that you should do before starting any type of maintenance on a motor is a visual inspection, a lot of times the trouble can be found just by looking, because if the problem is that bad then it should be very obvious by observation. After the load is disconnected, turn power on to try restarting the motor. Motors are susceptible to the gradual failure of their insulation resistance.

Find the percentage slip and number of poles of the induction motor. The three phase induction motor is the extensively used for various kinds of industrial drives. Such high currents may pose serious problems for the motor and the electrical system when large motors are started. Threephase dualvoltage motor insulation resistance testing. Now we are making control circuit diagram with following steps. The 3phase set of currents, each of equal magnitude and with a phase difference of 120 o, flow in the stator windings and generate a rotating field will constant magnitude. Identifying motor defects through fault zone analysis by.

Maintenance and troubleshooting three phase induction motor. If a single phase condition exists, correct the problem. Find the starting current of 10 hp, three phase 220 v a class motor. If not, check supply circuitry, breakers and condition of the motors power cord. The working of the threephase induction motor is based on the principle of electromagnetic induction. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Squirrel cage and induction type refer to the construction and operation of the rotor. In a three phase system if any two wires are reversed the motor will run in the opposite direction from the original direction. Take input voltage to the motor using the volt ohmmeter. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. Frequency of supply to the induction motor f pn120 12. The stator is supplied by a balanced 3 phase ac power.

A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. The best thing you could hope for is that the repair facility will call. How to troubleshoot a 3phase electric motor hunker. Code factor is a number which is reserved for class for example, all motors of class a have a fixed code factor which should be multiplied with rated hp in the above equation. They are used in situations where large power is required.

It should be less than the full load rating stamped on the nameplate only true for three phase motors. Three phase induction motors are one of the most popular electric motors commonly found in processing plants or any manufacturing concern. Record all nameplate information for the induction motor. How to troubleshoot motors and drives, starting at the inputs. However, you might end up needing to rewind or replace it.

Every good electrician knows the lead numbering sequence of three phase motors, or he has diagrams available for ready reference. If you find a phase toground short, a motor shop may be able to do an inplace repair for a large motor. They run at a constant speed from noload to the full load. Because of the critical roles these motors play in any plant, a failure of the motor, inability to start, noisy operation and sundry other problems need to be remedied as soon as possible to avoid costly production downtime. Refer to the wiring diagram to verify the motor is wired correctly. The basic steps in ascertaining the health of a threephase ac motor are given. Before troubleshooting the 3 phase induction motor, we must have to know.

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. Cause and analysis of stator and rotor failures in threephase squirrelcage induction motors abstract. A portion of rotating magnetic field in a three phase. Identifying motor defects through fault zone analysis. Installation and maintenance threephase induction motors. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. If you find a phase on phase short, the motor needs evaluation for a rewind or for replacement. In this case, power flows from the mechanical system, to the rotor circuit, then across the air gap to the stator circuit and external electrical system. If the motor problems cant be resolved with this list, please contact your supplier for assistance. Have a qualified technician check for the proper voltage in all three phases. An electrical motor is a device that has brought about one of the biggest advancements in the fields of engineering and technology ever since the invention.

Check the reason for the unbalanced threephase power supply, if it is caused by the power voltage or the motor itself. 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. For three phase motors, a three phase current sets up a rotating magnetic field that produces the starting torque without. You should also make a dc measurement of stator winding linetoline resistance. It is a maintenancefree, less noisy and efficient motor. Three phase induction motors draw six or more times rated current when started at rated voltage. In a 3 phase induction motor, there are so many fault that could occur during operation such as single phasing in which one of the three phase supply will be cut off but the motor will still run and produce a humming sound. Operating problems in other equipment connected to the same. The single phase induction motor is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. These motors run conveyor belts, pumps, fans, and many other applications. Motor was single phased as indicated by heat damage to one or two phases of the motor windings.

If the motor doesnt rotate in twophase operation, find the reason for phase loss and eliminate it. Learn how to troubleshoot 3 phase induction motor step by step with circuit. Induction motor problems and solutions pdf three phase induction motor 3 phase induction motor pdf the wound rotor induction motor speed control of induction motor three phase induction motor diagram speed control of induction motor by vf method blocked circle diagram of an induction motor single phase induction motor pdf free download speed. In troubleshooting a motor you may need to verify that the motor lead numbers are correct, and that there have been no electrical faults that create short circuits between the different phases. A threephase induction motor problem this application note describes how to set up, solve, and analyze the results of a twopole, three phase induction motor using rmxprt. Here we are giving you only overview on 3 phases induction motor. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. After looking at some of the considerations for fullvoltage starting, we will consider several. When three phase stator winding of an induction motor is energized from a 3 phase supply, a rotating magnetic field is set up which rotates around the stator at synchronous speed ns. Problems and premature failures often indicate input.

Follow the steps below to check for the most common problems for threephase motors. Deviations from rated fla could signify problems with the motor under test. A 3 phase induction motor can be used for different applications with various speed and load requirements. Chapter 3 induction motor and different speed control methods page no 3. Ac induction motors are also the most common motors used in main powered home appliances. The most popular type is the 3 phase, squirrelcage ac induction motor. The squirrel cage induction motor has limitations, which, if exceeded, will result in premature failure of the stator or rotor. How to test three phase ac motors learning electrical. In a 3 phase ac induction motor, there are three stator windings, each usually in two halves, with the rotor winding shortcircuited by end rings. Maintenance instructions for three phase induction motors frames 143t 449t 18060 109 ave edmonton, ab t5s 2k2. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Cause and analysis of stator and rotor failures in three. A threephase induction motor problem enginuity systems. Diagnostics of rotor and stator problems in industrial.