All removed components were evaluated, from mechanical fits to splitting the removed bearings to investigate their condition. [4] V. Peters, B. McKenney, A. Ogilvie, and C. Bond, “Continuous Reliability Enhancement for Wind (CREW) Database,” U.S. Fleet Public Report, Sandia National Labs, 2011. V. Peters, B. McKenney, A. Ogilvie, and C. Bond, “Continuous Reliability Enhancement for Wind (CREW) Database,” U.S. Fleet Public Report, Sandia National Labs, 2011. This article discusses a few common misconceptions of reliability and the assumptions that must be taken when approaching an RCFA. The trade-off is the potential de-rating of the generator. This may mean that wedges have to be manufactured in shorter sections versus one or two long wedges. In the world of reliability engineering, it is understood that the bathtub curve of reliability is mostly incorrect. The stripping process is unique to the investigating repair shop in that a warming process is used and the coils and insulation system can be removed intact for investigation. The purpose of the forensics is to follow a logical path as shown in, A Sample Flow For A Forensics Investigation. We recently published an article on the Power Electronics with the headline, “Unique Motor Uses Only Permanent Magnets – No Electric Power Required.”We received … Bottom coils were mixed tight and loose. This Eliminates The Excitation Losses In The Rotor, Which Otherwise Typically Represents 20 To 30 Percent Of The Total Generator … This guarantees smooth operation and maximum efficiency. In this case, the point where every generator inspected had failed was along the top edges of the coils, iron dust was collecting and penetrating the insulation as if it were magnetic termites. The Switch PMGs can be designed with an inner or outer rotor construction. The purpose of the forensics is to follow a logical path as shown in A Sample Flow For A Forensics Investigation chart. With the help of prior investigations it was discovered that root causes are often far simpler than previously determined and should be able to provide a logical and understandable cause-effect-cause relationship. This limits the ability of forensic investigators to evaluate all components, which may have partially led to incomplete material investigations in the past. NAVSEA Reliability-Centered Maintenance (RCM) Handbook, S9081-AB-GIB-010, Naval Sea Systems Command, US Navy, April 2007. Geoff Monteith beside a magnetic termite mound. In a few places, enough material was gathered to generate hot spots in the insulation system, burning the insulating material. In all cases the varnish penetration in the coils was excellent. Voltages ranged from 690 to 12,400 and across a series of turbine sizes between 1.5 and 2.5 MW. That is replacing a wear component with one more resistant to wear may extend the life of the system, but eliminating the source of wear on the component would provide a much longer impact overall. Each machine was carefully disassembled and investigated. The purpose of machine forensics is to preserve and investigate a failure beyond the obvious and look at design, procurement, human, physical, training, and other issues that create a chain of events that lead to turbine-component failure. The ages of the generators varied depending on a series of conditions including climate. Through a full review of the failure using Root-Cause-Failure-Analysis (RCFA) techniques, referred to as forensics in this article, it was discovered that wedge failure was not the case. One method would be to change the wedge material, which eliminates the iron dust and decrease its brittle state. This indicates that significant temperature swings were not only possible, they were probable. The Radial Flux Permanent Magnet Generator Is Synchronous, Where The Rotor Windings Have Been Replaced With Permanent Magnets. The generator failure is a symptom of system issues, not the actual cause of the system outage. Wind turbine generators tend to have a relatively high rate of failure. After viewing product detail pages, look here to find an easy way to navigate back to pages you are interested in. If Alewine and Chen are correct, this will reduce the primary cause of failure of the generator stators, which make up at least half of generator failures, thereby significantly increasing the availability of the wind fleet. You’re seeing this ad based on the product’s relevance to your search query. The material then collects and the iron dust begins to burrow as the coils wear more where the wedges are missing. Higher voltage stators used a significant amount of mica which eliminated partial discharge as a major failure mode. The key to resolving this particular failure mode and to extend the life of a generator is to break the chain of events. These PMGs have been developed to … The forensic investigations included multiple doubly-fed inverter generators and induction generators which had failed windings. Permanent Magnet Motors, 31ZY 6V/12V/24V 3500-8000RPM High Speed CW/CCW Permanent Magnet DC Motor for DIY Generator(12v4000) 4.1 out of 5 stars 9 $17.89 $ 17 . The wind generator is typically located in an area where the ambient temperature is present on all sides with a limited thermal barrier and is not rigidly attached to earth. Investigations also showed no sign of corona on any of the stators. But complex systems actually had random failures in which the systems break down. Each PMG topology is designed to best match specific wind conditions and the required turbine designs. A high speed, doubly-fed induction generator is the most common drivetrain topology in use today. A generator, however, makes for an expensive fuse, but it is acting as one just the same. Copyright © 2021 WTWH Media, LLC. The ‘magnetic’ termite mounds of monsoonal northern … The brown material is iron dust and some other evidence of tunneling caused by what’s called magnetic termites. Up to 100 years old, these structures are unique to the northern parts of Australia, including Litchfield National Park. We offer three different topologies to cover all wind power applications from 1 MW to 8 MW and higher: direct-driven, medium-speed and high-speed. Clip, share and download with the leading wind power engineering magazine today. In most cases, the generator components showed relatively little wear with the only visible defect being the winding fault. 5 Design Method for a Permanent-magnet Generator 55 5.1 Design Variables 55 5.2 Design Equations 58 5.2.1 General Definitions 58 5.2.2 Magnetic Circuit 60 5.2.3 Stator Inductance and Resistance 61 5.2.4 … ESR ESR and previous experiments support the pr esence of magnetic- eld-sensitive … So, why not just replace the magnetic wedge with a standard wedge? P. Lynding, S. Faulstitch, and P. Kuhn, “Establishing a Common Database for Turbine Failures,” Sandia National Labs, 2010. One of Litchfield National Park's most impressive sights is the hundreds of Magnetic Termite mounds standing up to two metres high on a wide flat plain. A discussion of a forensic analysis on a wind generator will follow. Eventually, the coils begin to move significantly and radially in the slot (towards and away from the rotor) as each coil magnetically loads and unloads. Ground-based generators, however, are firmly anchored to the floor of a facility and have a thermal insulating barrier at least on the underside of the machine or are located in a temperature-controlled environment. In effect, the coils begin to loosen. Is a Permanent Magnet Motor Feasible? These forces are significant, if coils have even a relatively small space for movement, forces can be significant and eventually result in ejecting wedges into the air gap. A review of the collected data indicates that the coils were assembled with relatively large clearances between the coils and the sides of the slots. The Tesla Magnetic Generator Review. Using this principle, you can plug an electric motor into a generator, start the generator and then turn the motor to generate an electric current. Thermal conditions – from the generator or environment. As the conducting coils move through the magnetic fields, the electrons in the wires … Stroll through the area and marvel at these enormous magnetic … A database called CREW[4], operated by Sandia National Labs for the U.S. Department of Energy, does not specify which components of a generator fails, just that generator failures accounts for 5.2% of wind-turbine unavailability in 2011. Initially, there was little reason behind whether a wedge was loose or tight until inspecting the packing below the wedge. A magnetic motor (or magnetic energy generator) can provide electricity without having to use fuel. The possibilities associated with the failure were then outlined: Coil movement – coils moving and knocking the wedges out of the stator, Dielectric stress – the electrical operating characteristics caused a breakdown of the insulation system, Transients – electrical component causes or lightning strikes, Partial discharge – corona effect on the insulation system, Varnish penetration – improperly varnished coils or voids in the insulation system, Vibrating wedges – wedges vibrate in the magnetic fields, Foreign object damage – parts or other objects loose in the generator. The ‘magnetic’ termite mounds of far northern Australia are imposing and spectacular but what intrigues any observer is how these tall, thin mounds tend to align in a north to south direction. The stator may still be VPI’d with the use of ripple-spring packing and in higher voltage applications, semi-conductive ripple springs are available. From a reliability-engineering standpoint, a study of the system and common failure characteristics allows for improvements. Of the 2011 Electrical Insulation Conference, IEEE, pp 392-397, 2011. In this case, the investigation is more at the component level, so the question as to the generator failing to operate has already been answered by choosing the generator’s failed condition.
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