Is there something like a "magnetic friction force"?
Is there something like a "magnetic friction force"?
Imagine that the dynamo is in a vacuum chamber. The rotating magnet does not touch the coil, and there is no air, so there is no aerodynamic drag.
So, I wonder if there is something like a "magnetic friction force", decelerating the rotating magnet. If so, is there a formula to calculate the force based on the magnetic field and distance?
Yes, it's often called magnetic damping, and for simple situations the value of the damping force can be predicted.
Given a conducting slab of resistivity ρ moving through magnetic field B with velocity v,
damping force F = B^2vV/ρ, where V is the volume of the conductor in the field.
Since it is velocity-dependent and against the direction of motion, it dissipates energy like a viscous force. As far as I know there is no friction force that behaves like static or dynamic friction that is a direct function of a magnetic field.
See the ref, p. 14.
The detailed situation you describe is more like simple generator loading, if the motor/generator is shorted or connected to an electrical load resistance. This is also a type of magnetic damping. In that case you can treat the motor as an ideal generator if you know its internal resistance and no-load speed at a given voltage. At speed w the generator generates a speed-dependent voltage V which results in a voltage- and load-dependent current I which results in dissipation of power P = VI. The load torque then is P/w.
Bulls Eye Dart Pen with Magnetic Base
Magnetic Power Generator for homes
From the time when solar power started to be globally known, there have turned up a great amount of other renewable energy systems that many people have proved and implemented in order to power their houses or apartments. Wind energy, geothermal energy and wave power are some examples of it.
In spite of the fact that each one of the mentioned solutions is a clean, non-polluting method that produce inexhaustible energy, their introduction is not altogether easy, when it comes to build a simple energy system for homes, either because of the technical complexity or, in many cases, because of the expensiveness of the necessary items that such systems consist of.
In this situation a major breakthrough came in when, already several years ago, the use of the magnetic forces of the planet were beginning to be applied in order to produce free, clean and renewable energy. In fact, the wise setup of a magnet set can make a wheel to spin incessantly, so that it can act as a turbine to offer us, in the end, free electricity. The advantage is that, unlike wind energy for instance, which depends on the magnitude of wind blowing through the mill's sails, a magnetic power generator has a permanent and consistent spinning.
The only significant disadvantage that the setting up of a home magnetic generator system has, is the room it takes from our home. So if we wish to introduce a magnetic energy solution in our homes, we should count on leaving a certain place or room to put our generator.
Aside from this little inconvenience, all the other aspects mean benefits: the material to construct and put together the magnetic power generator is relatively unexpensive and can easily be obtained at a hardware store in our town or city; the system does not generate any contaminating byproduct and, above all, we get totally free electricity.
Therefore, the implementation of a magnet-based generator to provide our house or apartment with free electricity is one of the best decisions we can ever take.
St. Christopher catholic statue with magnetic base 5cm, Magnetic Base 3G 5db CRC9 Antenna for HuaWei USB Modem, DIAL INDICATOR W/ MAGNETIC BASE IN CASE TOOLS , MAGNETIC BASE / SCRIBING BLOCK CNC TOOLMAKER HOME LATHE MODEL ENGINEER TOOL , BRINKMANN QBeam 12-Volt Marine Light 1,400 lumens 50-lb magnet base #80015011 , NEW 12 VOLT LED STROBE EMERGENCY BEACON MAGNETIC BASE POWER CORD!, Vintage Obsolete # 358 Yankee / 12 Volt Red Warning Light / Magnetic base, NEW Tool Logic ML2 Flashlight w/pivoting magnetic base also a magnetic keyring , Magnetic Base Carrot Shape Bottle Opener Kitchen Peeler, BRAND NEW COBRA MENS BASE BALL GOLF CAP BALLMARKER MAGNETIC FIELD VISOR, New Circular Magnetic UHF Antenna Base w 2.8 Meters Cable, STARRETT VINTAGE 657AA W/FINE ADJUSTMENT MAGNETIC BASE TOOLMAKER MACHINIST GRIND, Magnetic Base Holder Stand Standard 130 Lbs Pull, Magnetic Base Holders with 2" Dial Indicator White New, VINTAGE GWTW BRASS??? LAMP BASE! 4" FITTER. 8" X 8" X 3 1/4" MAGNET DONT STICK!, DVB-T External Digital TV Antenna mcx Magnetic base , Dial Indicator w/ Fine Adjustment Magnetic Base + Case, Fowler Dial Indicator and Magnetic Base Set, STARRETT 657U 657 U Flexible Post Magnetic Base Machinist Metal Worker Tool , 10 Warhammer Dark Elves Cold One Knights, magnetic bases and tray, Cabinet Hardware White Base 1.8" Single Magnetic Catch, Magnetic Rubber Base Round Shape Portable Handbag Hook, GOOSE NECK MAGNIFIER W/ MAGNETIC BASE, 20dBi WIFI Booster Wireless Antenna With Magnetic Base ForModem Router PCI Card, 12dBi WIFI RP-SMA Booster Wireless Antenna + Magnetic Base For Router PCI Card, Universal 3D Magnetic Base Holder for Dial Test Indicators Gauges, DIAL INDICATOR W/ MAGNETIC BASE + CASE Precision .001", manhattan supply Magnetic base for dial indicators NEW in box, STARRETT INDICATOR MAGNETIC BASE HOLDER #657B. NEW, STARRETT INDICATOR MAGNETIC BASE #657T.FLEX-O-POST, 2 X Magnetic Holder Base with Knob - 16Lbs (7.25kgs), Magnetic Extension Vee Base Block - As Photo 2 3/8" x 2 3/16" x 1 3/32", Indicator with Adjustment Magnetic Base , 0-1" DIAL INDICATOR GAUGE with MAGNETIC BASE + CASE New, Newport MMB Magnetic Base 30mm x 30mm x 35mm High 1/4-20, Sony PS3 Charge Base 3 Dual Port Controller Magnetic Charger Nyko (Playstation), Taxi Cab Roof Light w Magnetic Base Sign DC 12V Yellow, Starrett #645 Dial Indicator w/Magnetic Base, RETECH RG-MS7 SMA-F Female Pre-wired mini Magnet Base for Handheld Radio Antenna, Coolant Stand - Dual outlet - Magnetic Base, Dial Indicator & Magnetic Base Set , Master Magnetics Round Base Magnet-15-lb Cap #7216, FOWLER SYLVAC 905.4322.11 LEVER INDICATOR W/ MAGNETIC BASE, SUPER BRIGHT 4 LED LIGHT FLASHLIGHT MAGNETIC BASE STAND, 3D MINI UNIVERSAL MAGNETIC BASE HOLDER for INDICATOR, Mini Universal Magnetic Base Stand Holder for Indicator, MAGNETIC BASE 6" DIGITAL ELECTRONIC SCALE HEIGHT GAGE, Mini Locking Universal Magnetic Base Stand Holder, Magnetic Base For Dial Indicator / auto tool Zdmak, Anyform Magnetic Base w/ fine adjustment Model # MBA-2 New , MAGNETIC SHELL w-MAGNETS~Used~Handcrafted~For Black Base Handbag~~Butterflies~~, MAGNETIC SHELL w-MAGNETS~Used~Handcrafted~For Black Base Bag~Silver/white w-Cowl, MAGNETIC SHELL w-MAGNETS~Used~Handcrafted~For Black Base Handbag~~Yellow w-Sash~, SUNSUN JVP-102B JVP 102 WAVE MAKER MAGNET BASE PUMP !!, gap01 Magnetic Picture Collectable Print on Magnetic Base 4" x 2.7" (10x7cm), NIB Vintage Soundcraft Standard Magnetic Tape Acetate Base, High Quality Machinist Magnetic Base Tool Holder Strong Magnet Durable Precision, Summer Baby Touch Camera Replacement w/Adaptor, Base, Magnetic Charger - VGC, Two Way Radio Magnetic UHF Antenna Base w Coxial Cable, Fowler Dial Indicator Set with Magnetic Base - 1" Range,
