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Current Measurement in Power Electronic and Motor Drive Applications - a Comprehensive Study
Scholars' Mine Masters Theses Student Theses and Dissertations Fall 2007 Current measurement in power electronic and motor drive applications - a comprehensive study Asha Patel Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses Part of the Electrical and Computer Engineering Commons Department: Recommended Citation Patel, Asha, "Current measurement in power electronic and motor drive applications - a comprehensive study" (2007). Masters Theses. 4581. https://scholarsmine.mst.edu/masters_theses/4581 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. CURRENT MEASUREMENT IN POWER ELECTRONIC AND MOTOR DRIVE APPLICATIONS – A COMPREHENSIVE STUDY by ASHABEN MEHUL PATEL A THESIS Presented to the Faculty of the Graduate School of the UNIVERSITY OF MISSOURI-ROLLA In Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE IN ELECTRICAL ENGINEERING 2007 Approved by _______________________________ _______________________________ Dr. Mehdi Ferdowsi, Advisor Dr. Keith Corzine ____________________________ Dr. Badrul Chowdhury © 2007 ASHABEN MEHUL PATEL All Rights Reserved iii ABSTRACT Current measurement has many applications in power electronics and motor drives. Current measurement is used for control, protection, monitoring, and power management purposes. Parameters such as low cost, accuracy, high current measurement, isolation needs, broad frequency bandwidth, linearity and stability with temperature variations, high immunity to dv/dt, low realization effort, fast response time, and compatibility with integration process are required to ensure high performance of current sensors. -
An Introduction to Electrical Machines
An Introduction to Electrical Machines P. Di Barba, University of Pavia, Italy Academic year 2019-2020 Contents Rotating electrical machines (REM) • 1. Ampère law, Faraday principle, Lorentz force • 2. An overview of REM • 3. Rotating magnetic field Synchronous machine: alternator Asynchronous machine: induction motor Static electrical machines: transformer • 1. An overview of the device • 2. Principle of operation of a single-phase transformer • 3. Power (three-phase) transformer, signal transformer, autotransformer Rotating Electrical Machine Basically, it consists of: • an electric circuit (inductor) originating the magnetic field; • a magnetic circuit concentrating the field lines; • an electric circuit (armature) experiencing electrodynamical force (motor) or electromotive force (generator). stator inductor circuit air-gap rotor armature circuit stator + air-gap + rotor = magnetic circuit Principles of magnetics Ampère law i → b Principles of electromagnetism e Faraday-Lenz law transformer effect b(t) e(t), i(t) Principles of electromagnetism Faraday-Lenz law (motional effect) b + v → e Principles of electromechanichs Lorentz force b + i → F Magnetic field of a circular coil dl r n dB B i i B = 0 n 2r j axis 1 Rotating magnetic 2 B1 field (two-phase) I r axis w B2 B 0I 0I B1 = coswt n1 = coswt 2r 2r 0I 0I 0I B2 = coswt − n 2 = sin wt n 2 = −j sin wt 2r 2 2r 2r j axis Rotating magnetic 1 field (two-phase) II 2 B1 r axis w B2 B 0I 0I − jwt B = B1 + B2 = (coswt − jsin wt) = e 2r 2r Rotating magnetic j axis field (three-phase): -
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USOO678818OB2 (12) United States Patent (10) Patent No.: US 6,788,180 B2 Haugs et al. (45) Date of Patent: Sep. 7, 2004 (54) CONTROLLABLE TRANSFORMER 4.202,031. A 5/1980 Hesler et al. ................. 363/97 4,210,859 A 7/1980 Meretsky et al. ......... 323/44 R (75) Inventors: Espen Haugs, Sperrebotn (NO); Frank 5.936,503 A * 8/1999 Holmgren et al. ............ 336/60 Strand, Moss (NO) 6,232,865 B1 5/2001 Zinders et al. .............. 336/212 (73) Assignee: Magtech AS, Moss (NO) FOREIGN PATENT DOCUMENTS NO 146219 5/1982 (*) Notice: Subject to any disclaimer, the term of this NO 20002652 5/2000 patent is extended or adjusted under 35 WO WO 94/11891 5/1994 U.S.C. 154(b) by 0 days. WO WO 97/34210 9/1997 WO WO 98/31024 7/1998 (21) Appl. No.: 10/300,752 WO WO 01/90835 A1 11/2001 OTHER PUBLICATIONS (22) Filed: Nov. 21, 2002 International Search Report for PCT/NO 02/00434, Mar. 4, (65) Prior Publication Data 2003; 4 pages. Copy of Norwegian Search Report 20015689, Jul.10, 2002. US 2003/0117251A1 Jun. 26, 2003 Copy of International Search Report PCT/NO 02/00435, Related U.S. Application Data mailing date Mar. 6, 2003. 60) Provisional application No. 60/633,136, filed on Nov. 27, Copy of International Preliminary Examination Report PCT/ 2001 pp. NO 02/00435, Mar. 16, 2004. (30) Foreign Application Priority Data * cited by examiner Nov. 21, 2001 (NO) .............................................. O15689 Primary Examiner Anh Mai (51) Int. Cl." ................................................ H01F 27/34 (74) Attorney, Agent, or Firm Testa, Hurwitz & Thibeault, (52) U.S. -
615-4585 (10-110) Electromagnet Kit (Gilley Coil)
©2005 - v 8/05 615-4585 (10-110) Electromagnet Kit (Gilley Coil) as a result of the approach or departure Warranty Background Ideas of a magnetic field or as a result of We replace all defective or and Concepts for the strengthening or weakening of a missing parts free of charge. Ad- stationary one. The flow depends on ditional replacement parts may be Experiments change. ordered toll-free by referring to the An electric current is a flow of In Experiment 3, iron filings are part numbers above. All products electrons. The cause of electron flow used to outline magnetic lines of flux. warranted to be free from defect can vary. They may be made to flow If we move a magnet towards a coil for 90 days. Does not apply to due to electrostatic attraction or repul- (as in Experiment 1), the flux linking accident, misuse, or normal wear sion. Electrons in metallic substances with the coil is increased. During that and tear. are quite mobile and can be induced time when the magnet is approaching to flow by the presence of amagnetic the coil (i.e. flux is changing) an EMF field. is induced in the coil. The magnitude It is not fully understood what a of the EMF depends on how fast the magnetic field is. We describe it in flux is changing (i.e. how fast the mag- Introduction terms of its effect on materials. net is approaching.) The magnitude This apparatus is used to of the EMF can be calculated using Faraday's Law. demonstrate induced currents. -
Free-Energy Devices Author: Patrick J
A Practical Guide to Free-Energy Devices Author: Patrick J. Kelly Chapter 3: Motionless Pulsed Systems Note: If you are not at all familiar with basic electronics, you might find it easier to understand this chapter if you read chapter 12 first. The pulsed devices mentioned so far have had moving parts but rotating or fluctuating magnetic fields can be created without moving parts. An example of this is Graham Gunderson’s solid-state electric generator shown in US Patent Application 2006/0163971 A1 of 27th July 2006 which is shown on page A-1038 of the appendix. Another example is: Charles Flynn’s Magnetic Frame. Another device of this type comes from Charles Flynn. The technique of applying magnetic variations to the magnetic flux produced by a permanent magnet is covered in detail in the patents of Charles Flynn which are included in the Appendix. In his patent he shows techniques for producing linear motion, reciprocal motion, circular motion and power conversion, and he gives a considerable amount of description and explanation on each, his main patent containing a hundred illustrations. Taking one application at random: He states that a substantial enhancement of magnetic flux can be obtained from the use of an arrangement like this: Here, a laminated soft iron frame has a powerful permanent magnet positioned in it’s centre and six coils are wound in the positions shown. The magnetic flux from the permanent magnet flows around both sides of the frame. The full patent details of this system from Charles Flynn are in the Appendix, starting at page A - 338. -
Is Faraday's Disk Dynamo a Flux-Rule
Is Faraday’s Disk Dynamo a Flux-Rule Exception? Kirk T. McDonald Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (July 27, 2019; updated June 1, 2020) 1Problem In sec. 17.1 of [357], Feynman noted that the differential form of “Faraday’s law” is, ∂B ∇ × E = − , (1) ∂t and then argued that for a fixed loop one can deduce the integral form of this “law” as, d ∂B d E · dl = − · dArea = − (magnetic flux through loop), (2) loop dt surface of loop ∂t dt which is often called the “flux rule”. In sec. 17.2, he considered an experiment of Faraday 1 from 1831, sketched below, and claimed that this is an example of an exception to the “flux EMF × · rule”, where one should instead consider the motional = loop v B dl. However, a recent paper [520] expressed the view that Feynman and many others are “confused” about this example, and that it is well explained by the “correct” interpretation of the “flux rule”. What’s going on here? 2Solution In my view, the issue is that examples of magnetic induction can be analyzed more than one way, and whenever there is more than one way of doing anything, some people become overly enthusiastic for their preferred method, and imply that other methods are incorrect. 1See Art. 99 of [288]. Faraday’s dynamo is the inverse of a motor demonstrated by Barlow in 1822 [48], and discussed by Sturgeon in 1826 [72]. 1 As reviewed in Appendix A.17 below, Faraday discovered electromagnetic induction in 1831 [78], and gave an early version of what is now called Faraday’s law in Art.