3 phase induction motor numerical problems pdf

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Analysis of 3 phase Induction Motor Protection Using Numerical Relay

Some features of the site may not work correctly. Prabakaran and Shankar M. PrabakaranShankar M. Venkatesan Published Induction motors are widely used in industries and house hold applications due to high robustness, reliability, low cost and maintenance, high efficiency and long service life. Automation of group or individual drive needs monitoring and protection against hazards caused either by electrically or externally.

Consequence of that, motor protection is an emerging area of research. Save to Library. Create Alert. Launch Research Feed. Share This Paper. Figures and Tables from this paper. Figures and Tables. References Publications referenced by this paper. Fault diagnosis of three-phase induction motor: A review Malik A. KulkarniChetankumar Y. Patil On-line current monitoring to diagnose airgap eccentricity in large three-phase induction motors-industrial case histories verify the predictions Will T ThomsonD.

RankinDavid George Dorrell Engineering On-line current monitoring for fault diagnosis in inverter fed induction motors. Related Papers. By clicking accept or continuing to use the site, you agree to the terms outlined in our Privacy PolicyTerms of Serviceand Dataset License.The three-phase induction motors are the most widely used electric motors in the industry.

They work on the principle of electromagnetic induction. They run at essentially constant speed from no load to full load. However, the speed is frequency-dependent and consequently, these motors are not easily adapted to speed control. We usually prefer DC motors when large speed variations are required. Like any electric motor, a 3-phase induction motor has a stator and a rotor.

The stator carries a 3-phase winding called stator winding while the rotor carries a short-circuited winding called rotor winding. Only the stator winding is fed from the 3-phase supply. The rotor winding derives its voltage and power from the externally energized stator winding through electromagnetic induction and hence the name. A 3-phase induction motor has two main parts. The rotor is separated from the stator by a small air-gap which ranges from 0.

The stator consists of a steel frame that encloses a hollow, cylindrical core made up of thin laminations of silicon steel to reduce hysteresis and eddy current losses. A number of evenly spaced slots are provided on the inner periphery of the laminations. The insulated conductors are connected to form a balanced 3-phase star or delta connected circuit. The 3-phase stator winding is wound for a definite number of poles as per the requirement of speed.

Greater the number of poles, lesser is the speed of the motor and vice-versa. When 3-phase supply is given to the stator winding, a rotating magnetic field of constant magnitude is produced. This rotating field induces currents in the rotor by electromagnetic induction. For explaining the principle of operation of a three-phase induction motor, consider a portion of the three-phase induction motor as shown in the figure.

The working of the three-phase induction motor is based on the principle of electromagnetic induction. 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 N s.

For more details about rotating magnetic field, read Production of rotating magnetic field. This rotating field passes through the air gap and cuts the rotor conductors, which are stationary. Since the rotor circuit is short-circuited, currents start flowing in the rotor conductors.

How to troubleshoot 3 phase Induction motor : Step by Step Guide

The current-carrying rotor conductors are placed in the magnetic field produced by the stator. Consequently, a mechanical force acts on the rotor conductors.

3 phase induction motor numerical problems pdf

The sum of the mechanical forces on all the rotor conductors produces a torque which tends to move the rotor in the same direction as the rotating field. The fact that the rotor is urged to follow the stator field i. Now, the cause producing the rotor currents is the relative speed between the rotating field and the stationary rotor conductors. Hence to reduce this relative speed, the rotor starts running in the same direction as that of the stator field and tries to catch it. This is how a three-phase induction motor starts running.

We have seen above that the rotor rapidly accelerates in the direction of the rotating magnetic field. In practice, the rotor can never reach the speed of stator flux. If it did, there would be no relative speed between the stator field and rotor conductors, no induced rotor currents and, therefore, no torque to drive the rotor.

The friction and windage would immediately cause the rotor to slow down.To browse Academia. Skip to main content. Log In Sign Up. Hicham Moucharrafie. 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 of electricity. A motor is nothing but an electro-mechanical device that converts electrical energy into mechanical energy.

The very basic principle of functioning of an electrical motor lies on the fact that force is experienced in the direction perpendicular to the magnetic field and the current, when field and current are made to interact with each other. Two Types of Induction Motors Single phase induction motor: The single-phase induction motor is not self-starting. When the motor is connected to a single-phase power supply, the main winding carries an alternating current.

It is logical that the least expensive, most reduced upkeep sort engine ought to be utilized most regularly. These are of different types based on their way of starting since these are of not self starting. Those are split phase, shaded pole and capacitor motors. When the supply voltage is applied, current in the main winding lags the supply voltage because of the main winding impedance.

The angel between the two windings is sufficient phase difference to provide a rotating magnitude field to produce a starting torque. Applications of Single Phase Induction Motor These are used in low power applications and widely used in domestic applications as well as industrial.

We arrange the three-phase winding in such a manner in the slots that they produce one rotating magnetic field when we switch on the three-phase AC supply source. The stator of the motor consists of overlapping winding offset by an electrical angle of o. When we connect the primary winding, or the stator to a 3 phase AC source, it establishes rotating magnetic field which rotates at the synchronous speed. Slip, which varies from zero at synchronous speed and 1 when the rotor is at rest, determines the motor's torque.

Since the short-circuited rotor windings have small resistance, even a small slip induces a large current in the rotor and produces significant torque. These speed variations can cause load-sharing problems when differently sized motors are mechanically connected.

Various methods are available to reduce slip, VFDs often offering the best solution The rotor of three phase induction motor consists of a cylindrical laminated core with parallel slots that can carry conductors.

The conductors are heavy copper or aluminium bars fitted in each slot and short-circuited by the end rings.

Equivalent circuit of Induction Motor

The slots are not exactly made parallel to the axis of the shaft but are slotted a little skewed because this arrangement reduces magnetic humming noise and can avoid stalling of the motor. As the rotor winding in an induction motor are either closed through an external resistance or directly shorted by end ring, and cut the stator rotating magnetic field, an Emf is induced in the rotor copper bar and due to this Emf a current flows through the rotor conductor.

The working principle of three phase induction motor, it may be observed that the rotor speed should not reach the synchronous speed produced by the stator. If the speeds become equal, there would be no such relative speed, so no Emf induced in the rotor, and no current would be flowing, and therefore no torque would be generated.

Consequently, the rotor cannot reach the synchronous speed.Welcome Guest. The single-phase stator winding produces a With each load resistance receiving volts from its respective phase winding at the source, the current in each phase of this circuit will be The winding function used in this paper takes into account the sinusoidal variation of MMF on the slots.

Figure 3. For orthocyclic round coils three winding geometries can be defined:. Sine commutation allows for almost fully resonance-free operation of the motor. The combination of the star connections is depicted in form of a circle on the yellow contact bar. Winding Scheme Calculator. The rotor is often called a squirrel cage because it consists of a circular network of bars and rings that look a bit like a cage connected to an axle.

Hz for the 2- 4- and 6-pole version of 3-phase AC asynchronous motors in the 0.

3 phase induction motor numerical problems pdf

Every 3 phase motor has six 6 terminals with the supply voltage connected to three 3 of those terminals. Testing of a three-phase electric motor has to be conducted in order to get continuous services from motors without any break down or failure. We arrange the three-phase winding in such a manner in the slots that they produce one rotating magnetic field when we switch on the three-phase AC supply source.

Buck-boost transformers are designed to maximize the performance and life of electrical equipment. A derivation of the motor equations and the electrical and mechanical motor time In electrical engineering, coil winding is the manufacture of electromagnetic coils.

The stator consists of a ring with three pairs of coils, evenly spaced around the rotor. One is the main and How to find number of winding turns, number of winding wire and wire gauge Size of a three phase induction motor. Because the motor is an inductive load, there is a phase shift between the motor voltage and current.

The author of this calculator is Felix Niessen. The presentation will describe the basics of the three-phase The windings are.

3 phase induction motor numerical problems pdf

But please consider your Inverter current ampere rating same rated or higher than motor FLA. It may be hand started in either direction, coming up to speed in a few seconds. The winding coil is then inserted into the slots of the stator. Far too often motors are mismatched—or oversized—for the load they are intended to serve, or have been re-wound multiple times.

3 phase induction motor numerical problems pdf

WEG, which began in as a small factory of electric motors, has become a leading global Note: this formula applies to resistive loads only, i. Initial Data. Induction Motor Equivalent Circuit. AJAY B. One Phase Sequence Indicator. Each coil needs two slots. In this paper, a generalized formula is proposed for the selection of number of slots required for n-phase The applications of multi-phase motor are rail wagon tippler, Table 1: Three-phase two pole machine stator slots allocation.

What general calculation may be The voltage cycle of each line lags its predecessor by degrees -- L2 reaches its peak voltage after L1, and L3 reaches its peak voltage after L2. Record all nameplate information for the induction motor. When the V-phase winding is excited, the W-phase winding is in the open circuit mode to keep the current zero, so the Back EMF can be obtained exactly, and vice versa. In the calculation, there is the same magnitude of the applied.

The premise for motor operation is that if you can create a rotating magnetic field in the stator of the motor, it This represents the number of AC power lines supplying the motor.Ans: 3 Answer [2] Which of the following statements about a three-phase induction motor are false? Ans: 2 Answer [3] Which of the following statements is false when referring to a three-phase induction motor?

The frequency of the supply to the stator is: a 50 Hz b Hz c 25 Hz d Which of the following statements are false? Ans: 3 Answer [6] In a three-phase induction motor.

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3 phase motor winding calculation pdf

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Prabakaran and Shankar M. PrabakaranShankar M. Venkatesan Published Induction motors are widely used in industries and house hold applications due to high robustness, reliability, low cost and maintenance, high efficiency and long service life.

Automation of group or individual drive needs monitoring and protection against hazards caused either by electrically or externally. Consequence of that, motor protection is an emerging area of research. Save to Library. Create Alert. Launch Research Feed. Share This Paper. Figures and Tables from this paper.

Figures and Tables. References Publications referenced by this paper.

3 phase motor winding calculation pdf

Fault diagnosis of three-phase induction motor: A review Malik A. KulkarniChetankumar Y. Patil On-line current monitoring to diagnose airgap eccentricity in large three-phase induction motors-industrial case histories verify the predictions Will T ThomsonD.

RankinDavid George Dorrell Engineering On-line current monitoring for fault diagnosis in inverter fed induction motors. Related Papers. By clicking accept or continuing to use the site, you agree to the terms outlined in our Privacy PolicyTerms of Serviceand Dataset License.Troubles with the induction motors are generally divided into two categories.

One is the electrical faults, such as the various faults of switches, buttons, fuses, electric brushes, stator winding, rotor, starting equipment and so on.

The other is the mechanical problems, such as the problems of the bearing, fan blade, motor frame, coupling, end bell, bearing cover, spindle and so on.

Once the induction motor has any problem, there might be some abnormal phenomena, for instance, the rising temperature, over current, vibration and abnormal noise and so on. Therefore, learn about these phenomena, find out the cause, and then troubleshoot it.

The following is some common faults and troubleshooting method of three-phase induction motors for your reference. Why the revolving speed of the induction motor is lower than the rated value? The induction motor frame is electrified. The reason for the motor frame with electricity may be that the motor shell is not connected with the ground or has been damaged.

If the grounding equipment is damaged, the motor winding is affected with the damp and the insulation is aged. As a result, the current may leak out due to poor insulation. Or the outgoing line has been connected with the motor enclosure. For this problem, first of all, check if the motor grounding equipment is perfect and reconnect it with the ground.

If the motor get humid, it needs to be dried. The winding with seriously aged insulation should be exchanged. Buying a high quality induction motor will be easier than repairing one. ATO offers high reliability 3-phase induction motor, 1hp1. My Account Register Log in Wishlist 0. Back Servo Motors. Back AC Servo Motors. Back AC Gear Motors. Back Variable Frequency Drives. Back Transformers.


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