3 phase induction motor troubleshooting pdf errors

What causes a running 3 phase electric motor to suddenly. 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. Here we are giving you only overview on 3 phases induction motor. Have a qualified technician check for the proper voltage in all three phases. The working of the threephase induction motor is based on the principle of electromagnetic induction. What are the faults that can occur in a 3phase induction. 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. This is a routine procedure used when wanting to reverse the direction of a three phase motor. Frequency of supply to the induction motor f pn120 12. Check the source of power, overload, fuses, controls, etc. This situation often develops when theres an uneven distribution of single phase loads, either from a nearby panel or throughout the premises. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. 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. Installation and maintenance threephase induction motors.

Before troubleshooting the 3 phase induction motor, we must have to know. Operating problems in other equipment connected to the same. Motor was single phased as indicated by heat damage to one or two phases of the motor windings. Learn how to troubleshoot 3 phase induction motor step by step with circuit. Cause and analysis of stator and rotor failures in three. 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. 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. Take input voltage to the motor using the volt ohmmeter. 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. 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. Find the starting current of 10 hp, three phase 220 v a class motor. The squirrel cage induction motor has limitations, which, if exceeded, will result in premature failure of the stator or rotor. Now we are making control circuit diagram with following steps. The authors identify the various causes of stator and rotor failures.

If you find a phase on phase short, the motor needs evaluation for a rewind or for replacement. After looking at some of the considerations for fullvoltage starting, we will consider several. The most popular type is the 3 phase, squirrelcage ac induction motor. One single phase wattmeter plus miscellaneous apparatus as needed. Every good electrician knows the lead numbering sequence of three phase motors, or he has diagrams available for ready reference. For the motor, test the stator winding resistance phase to phase and phase toground. 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. If the motor problems cant be resolved with this list, please contact your supplier for assistance. 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.

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. A threephase induction motor problem enginuity systems. An electrical motor is an electromechanical device which converts electrical energy into mechanical energy. Cause and analysis of stator and rotor failures in threephase squirrelcage induction motors abstract. They are used in situations where large power is required. Record all nameplate information for the induction motor. The table below gives the commonly encountered problems in 3 phase squirrel cage. The single phase induction motor is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. An induction motor also known as an asynchronous motor is a commonly used ac electric motor. Three phase dualvoltage motor insulation resistance testing three phase dualvoltage motors are used for most daytoday operations in todays industrial plants.

Follow the steps below to check for the most common problems for threephase motors. In a three phase system if any two wires are reversed the motor will run in the opposite direction from the original direction. The motorspecified voltage must be present on all three phases. 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. It should be less than the full load rating stamped on the nameplate only true for three phase motors. How to troubleshoot a 3phase electric motor hunker.

It is a maintenancefree, less noisy and efficient motor. Motors are susceptible to the gradual failure of their insulation resistance. The three phase induction motors are simple in construction, rugged, low cost and easy to maintain. Three phase induction motors are one of the most popular electric motors commonly found in processing plants or any manufacturing concern. Induction motor solved problems examples, torque, starting torque, power developed. The stator is supplied by a balanced 3 phase ac power.

Squirrel cage and induction type refer to the construction and operation of the rotor. Maintenance instructions for three phase induction motors frames 143t 449t 18060 109 ave edmonton, ab t5s 2k2. Three phase induction motors draw six or more times rated current when started at rated voltage. These motors run conveyor belts, pumps, fans, and many other applications. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. They run at a constant speed from noload to the full load. Identifying motor defects through fault zone analysis. Such high currents may pose serious problems for the motor and the electrical system when large motors are started. One way to reduce the starting current is to start the motor at reduced voltage.

Ac induction motors are also the most common motors used in main powered home appliances. If the cause of the overheating was not located during steps 1 and 2, proceed. 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. If a single phase condition exists, correct the problem. 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 three phase motors, a three phase current sets up a rotating magnetic field that produces the starting torque without. 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. Faults identification in threephase induction motors using support. Refer to the wiring diagram to verify the motor is wired correctly. It supplies an induction motor ich has a full load speed of 144wh 0 rpm. If not, check supply circuitry, breakers and condition of the motors power cord. 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. Current is induced into the rotor as there are no brushes or other physical connections between the rotor and stator. This article describes ac electrical motor troubleshooting. If you find a phase toground short, a motor shop may be able to do an inplace repair for a large motor. These types of motors are known as selfstarting induction motors.

Check the reason for the unbalanced threephase power supply, if it is caused by the power voltage or the motor itself. Maintenance and troubleshooting three phase induction motor. If the motor doesnt rotate in twophase operation, find the reason for phase loss and eliminate it. The basic steps in ascertaining the health of a threephase ac motor are given. 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. How to troubleshoot motors and drives, starting at the inputs. How to test three phase ac motors learning electrical. Maintenance manual for three phase induction motors 5100 north ih35 round rock, tx. Lecture 6 three phase induction motors cairo university. A portion of rotating magnetic field in a three phase.

Identifying motor defects through fault zone analysis by. However, you might end up needing to rewind or replace it. If the cause of the overheating was not located during steps 1 and 2, proceed with causes 7a. 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. Find the percentage slip and number of poles of the induction motor. You should also make a dc measurement of stator winding linetoline resistance. Deviations from rated fla could signify problems with the motor under test. Problems and premature failures often indicate input.

As the current passes through the coils on opposite sides of the stator, a twopole electromagnet is established, creating a twopole motor. After the load is disconnected, turn power on to try restarting the motor. Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. The best thing you could hope for is that the repair facility will call. Threephase dualvoltage motor insulation resistance testing. Diagnostics of rotor and stator problems in industrial.