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# Vivek harmonics

how harmonics effect the system

how harmonics effect the system

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### Vivek harmonics

1. 1. ELECTRICAL SEMINAR PRESENTATION HARMONIC DISTORTION,EFFECTS AND MITIGATION VIVEK YADAV EN-3RD YEAR ROLL NUMBER-1274521014 10/04/15 1 of 28
2. 2. Understanding harmonics? How harmonics are produced? Mathematical analysis? Why to worry about harmonics? Causes of harmonics? What is THD? Its effect on power quality? Mitigation steps of harmonics? Advantages of harmonics? 10/04/15 2 of 28
3. 3. HARMONICS PRODUCER OF HARMONICS EFFECTS OF HARMONICS 10/04/15 3 of 28
4. 4.  Harmonics are defined as currents or voltages with frequencies that are integer multiples of the fundamental power frequency.( i.e. if the fundamental frequency is f, the harmonic have frequencies 2f, 3f, 4f, . . . etc)  The harmonics have the property that they are all periodic at the fundamental frequency, therefore the sum of harmonics is also  periodic at that frequency  Harmonic frequencies are equally spaced by the width of the fundamental frequency and can be found by repeatedly adding that frequency. For example, if the (first harmonic) is 25 Hz, the frequencies of the next harmonics are: 50 Hz (2nd harmonic), 75 Hz (3rd harmonic), 100 Hz (4th harmonic) etc. 10/04/15 4 of 28
5. 5. HOW ARE HARMONICS PRODUCED ? The distortion is mainly caused by Nonlinearity- In a linear circuit, the output response is directly proportional to the input. In an AC circuit, that means that the application of a sunusoidal voltage results in a sinusoidal current. As the instantanious voltage changes over the period of the sine wave, the instantanious current rises and falls in proportion to the voltage so that the waveform of the current is also a sine wave.  If a circuit is composed of ideal resistors, inductors and capacitors, it is a linear circuit because those components are linear. Real components can have some non-linearity because of non-linear characteristics such as the saturation of a magnetic circuit. There are degrees of linearity. AC motors are nearly linear. A motor's load current is a sine wave with only a little distortion.  A rectifier circuit with a capacitor filter is non-linear,another example of non linear circuit is lamp.(if we double the voltage from 10V to 20V current doubles in case of resistor but not in case of lamp hence lamp shows non linear characteristics. )  5 EE 6633 Semi nar 1
6. 6. 10/04/15 6 of 28 MAIN PRODUCERS OF HARMONICS Most harmonics come from loads such as induction and arc furnaces, and power electronics. Power electronics are the biggest culprit when it comes to producing harmonics. Static VAR compensators, variable frequency motor drives, and‐ switching power supplies are the greatest concern. (THESE ALL ARE NON LINEAR CIRCUITS.)
7. 7. LOADS PRODUCING HARMONIC CURRENTS ALL NON LINEAR LOADS PRODUCES HARMONIC DISTORTION IN VOLTAGE AND CURRENT SIGNALS.  Electronic lighting ballasts/Controls  Adjustable speed Motor-Drives  Electric Arc Welding Equipment  Solid state Industrial Rectifiers  Industrial Process Control Systems  Uninterruptible Power Supplies(ups)systems  Saturated Inductors/Transformers  LAN/Computer Networks These are some of examples of non linear elements which produces harmonic distortion in voltage and currents. 7 EE 6633 Semi nar 1
8. 8. WHY BOTHER ABOUT HARMONICS?  50-60% of all electrical Ac Systems in India operate with non-linear type of loads.  Power-Quality Issues & Problems  Damage to Power Factor Correction capacitors.  Waveform Distortion can create SAG/SWELL/NOTCHING/RINGING/…  All above can cause damage effects to consumer loads and power systems due to Over-Current/Over- Voltage or Waveform Distortion. Additional Power/Energy Losses(as eddy currents and hysteresis losses increases as they are directly proporional to frequency. 8 EE 6633 Semi nar 1
9. 9. 6-Pulse rectifier Dominant harmonics-5th ,7th . 12-pulse rectifier Dominant harmonics-11th ,13th .
10. 10. CALCULATION OF TOTAL HARMONIC DISTORTION(THD)  THD: Ratio of the RMS of the harmonic content to the RMS of the Fundamental  Current THD  Voltage THD 11 EE 6633 Semi nar 1
11. 11. THD 1.2% THD 78.3% Every Wave shape has Harmonic Distortion! Generally it is not economical to remove the harmonics having THD <5%
12. 12. NEGATIVE EFFECTS OF HARMONICS  Overheating and premature failure of distribution transformers . Increasing iron and copper losses or eddy currents due to stray flux losses(as they are directly proportional to frequency.)  Overheating and mechanical oscillations in the motor-load system. In electric motors, negative sequence harmonics (i.e. 5th, 11th, 17th), so called because their sequence (ABC or ACB) is opposite of the fundamental sequence, produce rotating magnetic fields. These fields rotate in the opposite direction of the fundamental magnetic field and could cause not only overheating but also mechanical oscillations in opposite directions. 13 EE 6633 Semi nar 1
13. 13. NEGATIVE EFFECTS OF HARMONICS (CONT’ D)  False or spurious Relay operations and trips of circuit breakers.  Mal-Operation/unstability of voltage regulator.  Power factor correction capacitor failure  Reactance (impedance)-Zc of a capacitor bank decreases as the frequency increases.(Z=1/(2*3.14*fC))  Capacitor bank acts as a sink for higher harmonic currents.  The System-Series and parallel Resonance can cause dielectric failure or rupture the power factor correction capacitor failure due to Currents,which is a very hazardous situation as maintenance of power factor will be affected. 14 EE 6633 Semi nar 1
14. 14. 10/04/15 15 of 28 OVERHEATING AND DAMAGE OF NEUTRAL GROUND CONDUCTERS In a three-phase, four-wire system, neutral conductors can be severely affected by nonlinear loads connected to the 220 V branch circuits. Under normal conditions for a balanced linear load, the fundamental 50 Hz portion of the phase currents will cancel in the neutral conductor. In a four-wire system with single-phase,in non-linear loads, certain odd-numbered harmonics called triplens — odd multiples of the third harmonic: 3rd, 9th, 15th, etc do not cancel, but rather add together in the neutral conductor. In systems with many single- phase, nonlinear loads, the neutral current can actually exceed the phase current. The danger here is excessive overheating because, unlike phase conductors, there are no circuit breakers in the neutral conductor to limit the current. This is the reason why mainly thickness of neutral conductors is kept greater than other phase conducters. FALSE OR SPURIOUS RELAY AND TRIP OF CIRCUIT BREAKER A peak-sensing, electronic trip circuit breaker responds to the peak of current waveform. As a result, it won’t always respond properly to harmonic currents. Since the peak of the harmonic current is usually higher than normal, this type of circuit breaker may trip prematurely at a low current. If the peak is lower than normal, the breaker may fail to trip when it should. Common thermal-magnetic circuit breakers use a bi-metallic trip mechanism that responds to the heating effect of the circuit current. They are designed to respond to the true-rms value of the current waveform and will trip when the trip mechanism gets too hot. This type of breaker has a good chance of protecting against harmonic current overloads.
15. 15. EFFECT OF HARMONIC ON METERS  Harmonics can produce significant errors in meters which sense the peak of waveform,then adjust it to”rms” by scaling by(2)^1/2.  Errors will not occur if wave is close to sinusoidal. PREVENTION “true rms” meters can mitigate the effects of harmonics as they sample the waveform,calculate rms value and display accurate results regardless of level of distortion. 10/04/15 16 of 28
16. 16. MEASUREMENT AND DETECTION TECHNIQUES DIGITAL OSCILLOSCOPE TRUE RMS MULTIMETER HARMONIC DISTORTION ANALYSER 10/04/15 17 of 28
17. 17. MEASUREMENT OF HARMONICS  Digital Oscilloscope: Wave shape, THD and Amplitude of each harmonic can be calculated with help of digital oscilloscope.  “True RMS” Multi-Meter: Giving correct readings for distortion-free sine waves and typically reading low when the current waveform is distorted “True RMS” Multi-Meter 2/23/200618 EE 6633 Semi nar 1
18. 18. DIGITAL OSCILLOSCOPE  When harmonics are present in considerable amount, their presence can be observed with an oscilloscope. The waveform displayed will either have unequal positive and negative peak values or will exhibit a change in shape. In either case, the oscilloscope will provide a qualitative check of harmonic distortion. However. the distortion must be fairly severe (around 10%) to be noted by an untrained observer. 10/04/15 19 of28
19. 19. HARMONIC DISTORTION ANALYZER  Most testing situations require a better quantitative measure of harmonic distortion. Harmonic distortion can be quantitatively measured very accurately with a harmonic distortion analyzer, which is generally referred to simply as a distortion analyzer.  A block diagram for a fundamental-suppression harmonic analyzer is shown in Figure.When the instrument is used. switch S, is set to the "set level" position, the band pass filter is adjusted to the fundamental frequency and the attenuator network is adjusted to obtain a full-scale voltmeter reading.  Switch S, is then set to the "distortion" position, the rejection filter(or we can say band stop filter) is turned to the fundamental frequency, and the attenuator is adjusted for a maximum reading on the voltmeter. 2/23/200620
20. 20. APPLICATIONS OF WAVE ANALYZERS  Amplitude measurement of a single component of a complex waveform.  Amplitude measurement in the presence of noise and interfering signals.  Measurement of signal energy within a well- defined bandwidth.
21. 21. POWER QUALITY ISSUE AND HARMONICS What is power quality? Why is power quality so important? Power quality problems due to harmonic distortion. 10/04/15 22 of 28
22. 22. WHAT IS POWER QUALITY? Power quality is simply the interaction of electronic equipment within the electrical environment. This consists of generators, Transformers, breakers, wiring and grounding.  Good power quality would be reliable supply of sinusoidal, 50Hz waveforms resulting in few operational anomalies. Example No. 1.Example No. 1. A standard 100-watt light bulb requires 220 volts to produce the designed light output (measured in lumens). If the voltage drops to 210 volts , the light bulb still works but puts out less lumens and is dimmer. If the voltage is removed as during a power outage, the light goes out. Either a low voltage or complete power outage does not damage the light bulb. If however the voltage rises to 240 volts , the light bulb will produce more lumens than it was intended to, causing overheating and stress to the filament wire. The bulb will fail much sooner than its expected design life; therefore, we could conclude that as far as a standard light bulb is concerned, a power quality issue that shortens bulb life is high voltage. We could also conclude that low voltage or a power outage would cause the lumen output to vary, which effects the intended use of the bulb. 10/04/15 23 of 28
23. 23. WHY IS POWER QUALITY SO IMPORTANT?  Power quality is an increasingly important issue for all electrical consumers .  Problems with powering and grounding can cause data and processing errors that affect production and service quality.  Each time production is interrupted as electrical consumer, you loses the margin on the product that is not manufactured and sold.  Surges and spikes (overpowering).  Harmonics ( current & voltage )  Voltage Fluctuations. 19-10-200524
24. 24. POWER QUALITY PROBLEMS DUE TO HARMONIC DISTORTION.  Harmonic current are generated to small extent and at low distortion levels by - 1- Generation equipment . 2- transmission equipment. 3- Distribution equipment . 4- Industrial load . 5- Domestic load. 19-10-200525
25. 25. HARMONIC EFFECTS ON POWER QUALITY  Equipments fail prematurely.  Decrease the efficiency of the electrical distribution and utilization network.  Causes grounding potential rise.  light flickering.  Faulty operation of Computerized data processing equipments and computer, networks and computer Faulty operation of Control devices, protective relays etc.  Extra loss in transformer, rotating machines etc.  Noise in electrical equipments.  Noise are generated by electronic devices. 19-10-200526
26. 26. MINIMIZING THE EFFECT OF HARMONICS Now days the receiver who utilizes the electrical power is supplied through to various electronic substances say AC- DC converter, Motor speed adjustable unit, various switching mode power supply system & computer process generator. All above discussed terminology are processed on diode, triode, transistor, thyristors which promote the nonlinearity Characteristics & due to this non linear function the receiver will be the cause of injecting the harmonic component in the distribution system & will also affect the other consumer by this pollution of harmonic in system. HENCE, harmonic filter technology is quite important for the power quality improvement of the system. The harmonic produce in the system is minimized by the use of various filters that are referring basically as ACTIVE FILTER & PASSIVE FILTER. 10/04/15 27 of 28
27. 27. 10/04/15 28 of 28 1. Over-sizing or derating of die installation – This solution does not eliminate harmonic currents flowing in the low voltage (less than 1000V AC) distribution system but masks the problem and avoid the consequences. The most widely implemented solution is over-sizing of the neutral conductor. In existing installation, the solution is to derate the electrical distribution equipment subjected to the harmonic currents. 2. Specially connected Transformers – this solution eliminates third order harmonic currents. It is a centralized solution for a set of single phase loads. 3. Series Reactors – this solution consists of connecting a reactor in series with non linear loads. 4. Tuned passive filters – a filter may be installed for one load or a set of loads. The filter rating must be coordinated with the reactive power requirements of the load 5. Active Harmonic Filters – The active harmonic fillers are used to introduce current component to cancel die harmonic components of the non linear loads. There are different types of active harmonic filters. 1. Series Filters: - This filter is connected in series with ac distribution network and compensates both the harmonic currents generated by the load and voltage distortion in the ac system. 2. Parallel Filters: - they are connected in parallel with the ac line and need to be sized for the harmonic currents drawn by the non linear loads. 3. Hybrid Filters: - It is a combination of active and passive filter and may be either series or parallel type. The passive filler carries out basic filtering (for example fifth order) and the active filter covers the other harmonics. Solution for Minimizing Harmonic Currents Effects
28. 28. SPECIALLY CONNECTED TRANSFORMERS Installation of any transformer -- delta-wye, deltazigzag, or wye-zigzag -  – provides an effective means of preventing triplen(3rd, 9th, 15th, etc.) harmonics from passing to the source side of thetransformer. The standard conservative design practice of using delta-wye transformers automatically results in electrical distribution systems with some inherent harmonic mitigation .With a standard delta-wye transformer installed, the triplen harmonics are not trapped in the transformer, but nor do they pass through the transformer. The sine waves induced on the windings are recombined at the nodes of the delta into new sine wave shapes that do not contain triplencomponents.The transformer’s reactance causes some attenuation of the harmonics and 2/23/200629 EE 6633 Semi nar 1
29. 29. 10/04/15 30 of 28 Line reactors can protect motors and reduce power line distortion from VFDs. A line reactor acts not only as a current-limiting device, but it also filters the waveform and attenuates electrical noise and transients associated with the system. You can install reactors in HVAC equipment, pumping equipment, machin tools, elevators, printing presses, UPS equipment, computer mainframes, robotics equipment, ski lifts, wind generators, electric cars, cranes, trams, and many other types of equipment, to extend the service life of the VFD and motor. Harmonic attenuation.  It is used typically on the line side of a VFD, as shown in Fig. 1 at right. Harmonic compensated line reactors are specially designed to handle the waveform's harmonic content. By inserting inductive reactance into the circuit, which is a high impedance to harmonic frequencies, line reactors reduce the amount of harmonics produced by a VFD system. This reduces input harmonics to 35% total harmonic current distortion (THID) Drive protection. In situations where you have drives located very close to the incoming facility power source, such as a substation, they may be susceptible to any incoming spikes and other transients. This is because there may not be enough impedance (in the form of transformers, power feeders, and the like) to help counteract these transient voltage spikes. This situation can damage the front end (diode section) of the drives or cause nuisance overvoltage tripping on the system Installing a 5% impedance line reactor at the input to each drive helps counteract line spikes, keeping them from tripping or damaging the drives. VFD protection.  The load reactor also acts as a current-limiting device to protect the drive under motor short circuit conditions. Here, the line reactor slows the rate of rise of the short-circuit current and limits the current to an acceptable level. LINE REACTORS
30. 30. 10/04/15 31 of 28 Summary of reactor performance.  The installation of load reactors with drives and motors can reduce the high-frequency currents in the motor and protect the motor from long lead effects. Basically, the reactor attempts to recreate a sine wave, thus improving overall system performance, reliability, and efficiency. It may reduce audible motor noise by as much as 3 dB to 5 dB. Tests have shown motor temperatures can drop as much as 20°C (more than double the motor life) when using a harmonic-compensated 5% impedance load reactor. On the line side, reactors stabilize the current waveform, which reduces harmonic distortion and the burden on upstream electrical equipment. By absorbing line spikes and filling some sags they can prevent overvoltage and undervoltage tripping problems. For example, when the utility switches power factor correction capacitors on the electrical power grid, it creates voltage spikes. The impedance of the reactor in the input circuit helps prevent these voltage spikes and virtually eliminates nuisance tripping of drives due to overvoltage. A line reactor can also filter out pulsed and notched distortion, which can minimize interference with other electronic equipment like computers, PLCs, telecommunications systems, instrumentation, and other VFDs. Use of line and load reactors increases the reliability, performance, and efficiency of VFD systems, extends the life of both drives and motors, and reduces the amount of energy consumed by the motor/drive system
31. 31. HARMONICS FILTER TYPES  Isolating harmonic current to protect electrical equipment from damage due to harmonic voltage distortion. PASSIVE FILTERS Uses combination of capacitors,inductor(reactors) and resistors  most common and available for all voltage levels.   ACTIVE FILTERS  Inserting negative phase compensating harmonics into the AC- Network, thus eliminating the undesirable harmonics on the AC Power Network.  Used only for for low voltage networks . HYBRID FILTERS The harmonic compensation can be obtained by Passive Filters (PF), Active Power Filters (APF) and hybrid filters (HPF) . PF and APF have some advantage and disadvantages, but hybrid active power filters contain their advantages but not their disadvantages. 2/23/200632 EE66 33 Smin ar 1
32. 32. 10/04/15 33 of 28 Passive filters Typical applications Industrial installations with a set of non-linear loads representing more than 500 kVA  (variable-speed drives, UPSs, rectifiers, etc.) Installations requiring power-factor correction. Installations where voltage distortion must be reduced to avoid disturbing sensitive  loads Installations where current distortion must be reduced to avoid overloads Operating principle An LC circuit, tuned to each harmonic order to be filtered, is installed in parallel with  the non-linear load (see Fig. ). This bypass circuit absorbs the harmonics, thus  avoiding their flow in the distribution network. Generally speaking, the passive filter is tuned to a harmonic order close to the order  to be eliminated. Several parallel-connected branches of filters can be used if a  significant reduction in the distortion of a number of harmonic orders is required.
33. 33. 10/04/15 Copyright © 2005 Rockwell Automation, Inc. All rights reserved. 34 of 28 34 PASSIVE HARMONIC FILTER M h p M o t o r L o a d T r a n s f o r m e r x f m r % Z D r iv e D C A C A C D C D C L in k C h o k e P a s s iv e F ilt e r Ia=f(S,... -25.00m -25.00m 24.90m 24.90m 0 0 -20.00m -20.00m -10.00m -10.00m 10.00m 10.00m 20.00m 20.00m -150.0 -150.0 150.0 0 0 -100.0 -100.0 -50.0 -50.0 50.0 50.0 100.0 100.0  Typical I(THD) of 5 to 8%
34. 34. 10/04/15 35 of 28 35 PASSIVE HARMONIC FILTER
35. 35. 10/04/15 36 of 28 Active filters (active harmonic conditioner) Typical applications •Commercial installations with a set of non-linear loads representing less than 500 kVA (variable-speed drives, UPSs, office equipment, etc.) •Installations where current distortion must be reduced to avoid overloads. Operating principle The basic principle of Shunt Active Filter is that it generates a current equal and opposite to the harmonic current drawn by the load and injects it to the point of coupling there by forcing the source current to be pure sinusoidal.
36. 36. 10/04/15 37 of 28 ACTIVE FILTER CONCEPT I source = I rectifier + I filter 1st 5th 7th 11th 13th I rectifier I filter I source I source I filter I rectifier • High Filter Converter ratings: ~ 1/3 of Drive kVA • Multi-functional: reactive power factor compensation, voltage and load balancing
37. 37. 10/04/15 Copyright © 2005 Rockwell Automation, Inc. All rights reserved. 38 of 28 38 ACTIVE HARMONIC FILTER  Typical I(THD) of 3 to 6% Ia=f(S,... -25.00m -25.00m 24.90m 24.90m 0 0 -20.00m -20.00m -10.00m -10.00m 10.00m 10.00m 20.00m 20.00m -150.0 -150.0 150.0 0 0 -100.0 -100.0 -50.0 -50.0 50.0 50.0 100.0 100.0 Current from Transformer M D r iv e h p M o t o r L o a d T r a n s f o r m e r D C A C D C L in k C h o k ex f m r % Z A C D C I f u n d I f u n d + I h a r m I h a r m A c t iv e F ilt e r A C D C
38. 38. 10/04/15 39 of 28 39 ACTIVE HARMONIC FILTER
39. 39. 10/04/15 40 of 28 Hybrid filters Typical applications Industrial installations with a set of non-linear loads representing more than 500 kVA (variable-speed drives, UPSs, rectifiers, etc.) •Installations requiring power-factor correction •Installations where voltage distortion must be reduced to avoid disturbing sensitive loads •Installations where current distortion must be reduced to avoid overloads •Installations where strict limits on harmonic emissions must be met Operating principle Passive and active filters are combined in a single system to constitute a hybrid filter (see Fig). This new filtering solution offers the advantages of both types of filters and covers a wide range of power and performance levels.
40. 40. ADVANTAGES AND DISADVANTAGE OF ACTIVE FILTERS ADVANTAGES  FLEXIBILITY IS HIGHER  LOWER COST AS COMPARED TO PASSIVE FILTERS DISADVANTAGES  SENSITIVE TO TEMPERATURE.  GOOD PERFORMANCE ACHIVED TILL 500KHZ 10/04/15 41 of 28
41. 41. 10/04/15 42 of 28 PERFORMANCE CHART OF VARIOUS MITIGATION TECHNIQUES MITIGATION TECHNIQUES A. 6-pulse, no link choke B. 6-pulse, with link choke C. Input line reactor D. Tuned and non-tuned filters E. 12-pulse with auto transformer F. 12-pulse with isolation transformer G. 18-pulse with auto transformer H. 18-pulse with isolation transformer I. Regenerative active front end J. Active power filter
42. 42. BENEFICIAL USE OF HARMONICS TISSUE HARMONIC IMAGING IN ULTRA SOUND MACHINES. HARMONICS OF HEALTH. CHORUS MOTORS. 10/04/15 43 of 28
43. 43. 10/04/15 44 of 28 Tissue Harmonics Imaging This is the most common advanced imaging technology and is found on about 90% of available new and refurbished ultrasound machines. What is it? Harmonics imaging allows the ultrasound to identify body tissue and reduce noise in the image. It does this by sending and receiving signals at two different ultrasound frequencies. For example, with harmonics on, a probe would emit a frequency of 2MHz, but it would only “listen” for a 4MHz frequency. This improves image quality because body tissue reflects sound at twice the frequency that was initially sent, which results in a cleaner image that better displays body tissue without extra artifact. The following image shows a demonstration of a signal sent at 7 Mhz and received at 14Mhz. You can see how body tissue is better defined and image artifact is reduced. Tissue Harmonics allows the ultrasound to identify tissue better and reduce artifact or “noise” in the image. Adjusting levels of harmonics helps optimize an ultrasound image Tissue Harmonics allows the ultrasound to identify tissue better and reduce artifact or “noise” in the image. Adjusting levels of harmonics helps optimize an ultrasound image
44. 44. 10/04/15 45 of 28 The basic principle of healing with sound is the concept of resonance (the vibratory frequency of an object.) The entire Universe is in a state of vibration. This includes human beings. Every organ, cell, bone, tissue and liquid of the body, and also the electromagnetic fields which surround the body (aura), has a healthy vibratory frequency. If we are not resonating with some part of ourselves or of our surroundings, we become dissonant and therefore unhealthy. Our naturally healthy frequency becomes a frequency that vibrates without harmony, creating illness. Through the use of sound, and particularly our own voices, we can project the correct resonant frequency toward and into, any unhealthy part of ouselves, thus returning it to its normal frequency, and resulting in a HEALING. This occurs through sympathetic resonance when one vibrating object influences another vibrating or even stationary object, causing changes in its vibratory rate. An extreme example is a singer causing glass to shatter. This traditional medical technique of healing usingtuning forks is very common in SPAIN and gainig popularity in other parts of world. Sound has the capacity to change form at the physical, etheric, emotional and spiritual levels, and also all these levels simultaneously. Harmonics for Health
45. 45. 10/04/15 46 of 28 •Benefits Greater power density than any other technology •Smaller drives for the same load •High reliability from the use of standard modules and materials Chorus Meshcon allows unprecedented performance in the motor and drive, providing the ideal solutions for most traction and start-stop motor applications, including such growth businesses as integrated starter-alternators for automobiles, as well as more traditional applications such as conveyors, locomotives, cargo handling, hoists, printing presses, or any application requiring large startup torques and smaller high speed loads.  How does it work? The Chorus Star concept utilizes concentrated, high phase order windings which allows the beneficial use of harmonics (temporal, spatial, and overload). Consequently, a Chorus machine can achieve much higher torque densities than a traditional 3 phase motor, but with no cost penalty. Chorus Star machines are superior to three-phase machines as well as permanent-magnet machines.  CHORUS MOTORS
46. 46. CONCLUSIONS  The harmonic distortion principally comes from Nonlinear-Type of Loads.  The greater application of power electronics is causing increased level of harmonics.  Harmonic distortion can cause serious Failure/Damage problems.  Harmonics are important aspect of power operation that requires Mitigation!!  Over-Sizing and Power Filtering methods are commonly used to limit Overheating Effects of Sustained Harmonics. 2/23/200647 EE 6633 Semi nar 1
47. 47. 10/04/15 48 of 28 THANK YOU