Induction Motors Introduction Threephase induction motors are the
![Induction Motors Induction Motors](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-1.jpg)
![Introduction Ø Three-phase induction motors are the most common and frequently encountered machines in Introduction Ø Three-phase induction motors are the most common and frequently encountered machines in](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-2.jpg)
![Construction Ø An induction motor has two main parts - a stationary stator • Construction Ø An induction motor has two main parts - a stationary stator •](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-3.jpg)
![Construction - a revolving rotor • • Ø composed of punched laminations, stacked to Construction - a revolving rotor • • Ø composed of punched laminations, stacked to](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-4.jpg)
![Construction Squirrel cage rotor Wound rotor Notice the slip rings Construction Squirrel cage rotor Wound rotor Notice the slip rings](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-5.jpg)
![Construction Slip rings Cutaway in a typical woundrotor IM. Notice the brushes and the Construction Slip rings Cutaway in a typical woundrotor IM. Notice the brushes and the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-6.jpg)
![Rotating Magnetic Field Ø Ø Balanced three phase windings, i. e. mechanically displaced 120 Rotating Magnetic Field Ø Ø Balanced three phase windings, i. e. mechanically displaced 120](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-7.jpg)
![Rotating Magnetic Field Rotating Magnetic Field](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-8.jpg)
![Principle of operation Ø Ø This rotating magnetic field cuts the rotor windings and Principle of operation Ø Ø This rotating magnetic field cuts the rotor windings and](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-9.jpg)
![Induction motor speed Ø At what speed will the IM run? - - Can Induction motor speed Ø At what speed will the IM run? - - Can](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-10.jpg)
![Induction motor speed Ø Ø So, the IM will always run at a speed Induction motor speed Ø Ø So, the IM will always run at a speed](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-11.jpg)
![The Slip Where s is the slip Notice that : if the rotor runs The Slip Where s is the slip Notice that : if the rotor runs](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-12.jpg)
![Example 7 -1 (pp. 387 -388) A 208 -V, 10 hp, four pole, 60 Example 7 -1 (pp. 387 -388) A 208 -V, 10 hp, four pole, 60](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-13.jpg)
![Solution 1. 2. 3. 4. Solution 1. 2. 3. 4.](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-14.jpg)
![Problem 7 -2 (p. 468) Problem 7 -2 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-15.jpg)
![Equivalent Circuit Equivalent Circuit](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-16.jpg)
![Power losses in Induction machines Ø Copper losses - Ø Ø Ø Copper loss Power losses in Induction machines Ø Copper losses - Ø Ø Ø Copper loss](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-17.jpg)
![Power flow in induction motor Power flow in induction motor](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-18.jpg)
![Power relations Power relations](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-19.jpg)
![Equivalent Circuit Ø We can rearrange the equivalent circuit as follows Actual rotor resistance Equivalent Circuit Ø We can rearrange the equivalent circuit as follows Actual rotor resistance](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-20.jpg)
![Power relations Power relations](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-21.jpg)
![Torque, power and Thevenin’s Theorem Ø Thevenin’s theorem can be used to transform the Torque, power and Thevenin’s Theorem Ø Thevenin’s theorem can be used to transform the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-22.jpg)
![Torque, power and Thevenin’s Theorem Torque, power and Thevenin’s Theorem](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-23.jpg)
![Torque, power and Thevenin’s Theorem Then the power converted to mechanical (Pconv) And the Torque, power and Thevenin’s Theorem Then the power converted to mechanical (Pconv) And the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-24.jpg)
![Torque, power and Thevenin’s Theorem Torque, power and Thevenin’s Theorem](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-25.jpg)
![Torque-speed characteristics Typical torque-speed characteristics of induction motor Torque-speed characteristics Typical torque-speed characteristics of induction motor](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-26.jpg)
![Maximum torque Ø Ø Maximum torque occurs when the power transferred to R 2/s Maximum torque Ø Ø Maximum torque occurs when the power transferred to R 2/s](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-27.jpg)
![Maximum torque Ø The corresponding maximum torque of an induction motor equals Ø The Maximum torque Ø The corresponding maximum torque of an induction motor equals Ø The](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-28.jpg)
![Maximum torque Ø Ø Rotor resistance can be increased by inserting external resistance in Maximum torque Ø Ø Rotor resistance can be increased by inserting external resistance in](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-29.jpg)
![Maximum torque Effect of rotor resistance on torque-speed characteristic Maximum torque Effect of rotor resistance on torque-speed characteristic](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-30.jpg)
![Problem 7 -5 (p. 468) Problem 7 -5 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-31.jpg)
![Solution to Problem 7 -5 (p. 468) Solution to Problem 7 -5 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-32.jpg)
![Problem 7 -7 (pp. 468 -469) Problem 7 -7 (pp. 468 -469)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-33.jpg)
![Solution to Problem 7 -7 (pp. 468 -469) Solution to Problem 7 -7 (pp. 468 -469)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-34.jpg)
![Solution to Problem 7 -7 (pp. 468 -469) – Cont’d Solution to Problem 7 -7 (pp. 468 -469) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-35.jpg)
![Solution to Problem 7 -7 (pp. 468 -469) – Cont’d Solution to Problem 7 -7 (pp. 468 -469) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-36.jpg)
![Problem 7 -19 (p. 470) Problem 7 -19 (p. 470)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-37.jpg)
![Solution to Problem 7 -19 (pp. 470) Solution to Problem 7 -19 (pp. 470)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-38.jpg)
![Solution to Problem 7 -19 (pp. 470) – Cont’d Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-39.jpg)
![Solution to Problem 7 -19 (pp. 470) – Cont’d Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-40.jpg)
![Solution to Problem 7 -19 (pp. 470) – Cont’d Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-41.jpg)
- Slides: 41
![Induction Motors Induction Motors](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-1.jpg)
Induction Motors
![Introduction Ø Threephase induction motors are the most common and frequently encountered machines in Introduction Ø Three-phase induction motors are the most common and frequently encountered machines in](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-2.jpg)
Introduction Ø Three-phase induction motors are the most common and frequently encountered machines in industry - - simple design, rugged, low-price, easy maintenance wide range of power ratings: fractional horsepower to 10 MW run essentially as constant speed from zero to full load speed is power source frequency dependent • • not easy to have variable speed control requires a variable-frequency power-electronic drive for optimal speed control
![Construction Ø An induction motor has two main parts a stationary stator Construction Ø An induction motor has two main parts - a stationary stator •](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-3.jpg)
Construction Ø An induction motor has two main parts - a stationary stator • • consisting of a steel frame that supports a hollow, cylindrical core, constructed from stacked laminations (why? ), having a number of evenly spaced slots, providing the space for the stator winding Stator of IM
![Construction a revolving rotor Ø composed of punched laminations stacked to Construction - a revolving rotor • • Ø composed of punched laminations, stacked to](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-4.jpg)
Construction - a revolving rotor • • Ø composed of punched laminations, stacked to create a series of rotor slots, providing space for the rotor winding one of two types of rotor windings conventional 3 -phase windings made of insulated wire (wound-rotor) » similar to the winding on the stator aluminum bus bars shorted together at the ends by two aluminum rings, forming a squirrel-cage shaped circuit (squirrel-cage) Two basic design types depending on the rotor design - squirrel-cage wound-rotor
![Construction Squirrel cage rotor Wound rotor Notice the slip rings Construction Squirrel cage rotor Wound rotor Notice the slip rings](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-5.jpg)
Construction Squirrel cage rotor Wound rotor Notice the slip rings
![Construction Slip rings Cutaway in a typical woundrotor IM Notice the brushes and the Construction Slip rings Cutaway in a typical woundrotor IM. Notice the brushes and the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-6.jpg)
Construction Slip rings Cutaway in a typical woundrotor IM. Notice the brushes and the slip rings Brushes
![Rotating Magnetic Field Ø Ø Balanced three phase windings i e mechanically displaced 120 Rotating Magnetic Field Ø Ø Balanced three phase windings, i. e. mechanically displaced 120](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-7.jpg)
Rotating Magnetic Field Ø Ø Balanced three phase windings, i. e. mechanically displaced 120 degrees form each other, fed by balanced three phase source A rotating magnetic field with constant magnitude is produced, rotating with a speed Where fe is the supply frequency and P is the no. of poles and nsync is called the synchronous speed in rpm (revolutions per minute)
![Rotating Magnetic Field Rotating Magnetic Field](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-8.jpg)
Rotating Magnetic Field
![Principle of operation Ø Ø This rotating magnetic field cuts the rotor windings and Principle of operation Ø Ø This rotating magnetic field cuts the rotor windings and](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-9.jpg)
Principle of operation Ø Ø This rotating magnetic field cuts the rotor windings and produces an induced voltage in the rotor windings Due to the fact that the rotor windings are short circuited, for both squirrel cage and wound-rotor, and induced current flows in the rotor windings The rotor current produces another magnetic field A torque is produced as a result of the interaction of those two magnetic fields Where ind is the induced torque and BR and BS are the magnetic flux densities of the rotor and the stator respectively
![Induction motor speed Ø At what speed will the IM run Can Induction motor speed Ø At what speed will the IM run? - - Can](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-10.jpg)
Induction motor speed Ø At what speed will the IM run? - - Can the IM run at the synchronous speed, why? If rotor runs at the synchronous speed, which is the same speed of the rotating magnetic field, then the rotor will appear stationary to the rotating magnetic field and the rotating magnetic field will not cut the rotor. So, no induced current will flow in the rotor and no rotor magnetic flux will be produced so no torque is generated and the rotor speed will fall below the synchronous speed When the speed falls, the rotating magnetic field will cut the rotor windings and a torque is produced
![Induction motor speed Ø Ø So the IM will always run at a speed Induction motor speed Ø Ø So, the IM will always run at a speed](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-11.jpg)
Induction motor speed Ø Ø So, the IM will always run at a speed lower than the synchronous speed The difference between the motor speed and the synchronous speed is called the Slip Where nslip= slip speed nsync= speed of the magnetic field nm = mechanical shaft speed of the motor
![The Slip Where s is the slip Notice that if the rotor runs The Slip Where s is the slip Notice that : if the rotor runs](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-12.jpg)
The Slip Where s is the slip Notice that : if the rotor runs at synchronous speed s=0 if the rotor is stationary s=1 Slip may be expressed as a percentage by multiplying the above eq. by 100, notice that the slip is a ratio and doesn’t have units
![Example 7 1 pp 387 388 A 208 V 10 hp four pole 60 Example 7 -1 (pp. 387 -388) A 208 -V, 10 hp, four pole, 60](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-13.jpg)
Example 7 -1 (pp. 387 -388) A 208 -V, 10 hp, four pole, 60 Hz, Y-connected induction motor has a full-load slip of 5 percent 1. 2. 3. 4. What is the synchronous speed of this motor? What is the rotor speed of this motor at rated load? What is the rotor frequency of this motor at rated load? What is the shaft torque of this motor at rated load?
![Solution 1 2 3 4 Solution 1. 2. 3. 4.](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-14.jpg)
Solution 1. 2. 3. 4.
![Problem 7 2 p 468 Problem 7 -2 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-15.jpg)
Problem 7 -2 (p. 468)
![Equivalent Circuit Equivalent Circuit](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-16.jpg)
Equivalent Circuit
![Power losses in Induction machines Ø Copper losses Ø Ø Ø Copper loss Power losses in Induction machines Ø Copper losses - Ø Ø Ø Copper loss](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-17.jpg)
Power losses in Induction machines Ø Copper losses - Ø Ø Ø Copper loss in the stator (PSCL) = I 12 R 1 Copper loss in the rotor (PRCL) = I 22 R 2 Core loss (Pcore) Mechanical power loss due to friction and windage How this power flow in the motor?
![Power flow in induction motor Power flow in induction motor](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-18.jpg)
Power flow in induction motor
![Power relations Power relations](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-19.jpg)
Power relations
![Equivalent Circuit Ø We can rearrange the equivalent circuit as follows Actual rotor resistance Equivalent Circuit Ø We can rearrange the equivalent circuit as follows Actual rotor resistance](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-20.jpg)
Equivalent Circuit Ø We can rearrange the equivalent circuit as follows Actual rotor resistance Resistance equivalent to mechanical load
![Power relations Power relations](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-21.jpg)
Power relations
![Torque power and Thevenins Theorem Ø Thevenins theorem can be used to transform the Torque, power and Thevenin’s Theorem Ø Thevenin’s theorem can be used to transform the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-22.jpg)
Torque, power and Thevenin’s Theorem Ø Thevenin’s theorem can be used to transform the network to the left of points ‘a’ and ‘b’ into an equivalent voltage source V 1 eq in series with equivalent impedance Req+j. Xeq
![Torque power and Thevenins Theorem Torque, power and Thevenin’s Theorem](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-23.jpg)
Torque, power and Thevenin’s Theorem
![Torque power and Thevenins Theorem Then the power converted to mechanical Pconv And the Torque, power and Thevenin’s Theorem Then the power converted to mechanical (Pconv) And the](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-24.jpg)
Torque, power and Thevenin’s Theorem Then the power converted to mechanical (Pconv) And the internal mechanical torque (Tconv)
![Torque power and Thevenins Theorem Torque, power and Thevenin’s Theorem](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-25.jpg)
Torque, power and Thevenin’s Theorem
![Torquespeed characteristics Typical torquespeed characteristics of induction motor Torque-speed characteristics Typical torque-speed characteristics of induction motor](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-26.jpg)
Torque-speed characteristics Typical torque-speed characteristics of induction motor
![Maximum torque Ø Ø Maximum torque occurs when the power transferred to R 2s Maximum torque Ø Ø Maximum torque occurs when the power transferred to R 2/s](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-27.jpg)
Maximum torque Ø Ø Maximum torque occurs when the power transferred to R 2/s is maximum. This condition occurs when R 2/s equals the magnitude of the impedance Req + j (Xeq + X 2)
![Maximum torque Ø The corresponding maximum torque of an induction motor equals Ø The Maximum torque Ø The corresponding maximum torque of an induction motor equals Ø The](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-28.jpg)
Maximum torque Ø The corresponding maximum torque of an induction motor equals Ø The slip at maximum torque is directly proportional to the rotor resistance R 2 The maximum torque is independent of R 2 Ø
![Maximum torque Ø Ø Rotor resistance can be increased by inserting external resistance in Maximum torque Ø Ø Rotor resistance can be increased by inserting external resistance in](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-29.jpg)
Maximum torque Ø Ø Rotor resistance can be increased by inserting external resistance in the rotor of a wound-rotor induction motor. The value of the maximum torque remains unaffected but the speed at which it occurs can be controlled.
![Maximum torque Effect of rotor resistance on torquespeed characteristic Maximum torque Effect of rotor resistance on torque-speed characteristic](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-30.jpg)
Maximum torque Effect of rotor resistance on torque-speed characteristic
![Problem 7 5 p 468 Problem 7 -5 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-31.jpg)
Problem 7 -5 (p. 468)
![Solution to Problem 7 5 p 468 Solution to Problem 7 -5 (p. 468)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-32.jpg)
Solution to Problem 7 -5 (p. 468)
![Problem 7 7 pp 468 469 Problem 7 -7 (pp. 468 -469)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-33.jpg)
Problem 7 -7 (pp. 468 -469)
![Solution to Problem 7 7 pp 468 469 Solution to Problem 7 -7 (pp. 468 -469)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-34.jpg)
Solution to Problem 7 -7 (pp. 468 -469)
![Solution to Problem 7 7 pp 468 469 Contd Solution to Problem 7 -7 (pp. 468 -469) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-35.jpg)
Solution to Problem 7 -7 (pp. 468 -469) – Cont’d
![Solution to Problem 7 7 pp 468 469 Contd Solution to Problem 7 -7 (pp. 468 -469) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-36.jpg)
Solution to Problem 7 -7 (pp. 468 -469) – Cont’d
![Problem 7 19 p 470 Problem 7 -19 (p. 470)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-37.jpg)
Problem 7 -19 (p. 470)
![Solution to Problem 7 19 pp 470 Solution to Problem 7 -19 (pp. 470)](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-38.jpg)
Solution to Problem 7 -19 (pp. 470)
![Solution to Problem 7 19 pp 470 Contd Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-39.jpg)
Solution to Problem 7 -19 (pp. 470) – Cont’d
![Solution to Problem 7 19 pp 470 Contd Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-40.jpg)
Solution to Problem 7 -19 (pp. 470) – Cont’d
![Solution to Problem 7 19 pp 470 Contd Solution to Problem 7 -19 (pp. 470) – Cont’d](https://slidetodoc.com/presentation_image/09390e7102bcd11c9be4fe01dac1cebd/image-41.jpg)
Solution to Problem 7 -19 (pp. 470) – Cont’d
Insidan region jh
Induction motors procurement
Swot analysis of tata company
Introduction of electric motor
Introduction of three phase induction motor
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