A mon (humble ) avis, si tu n'as pas tes fils "alignés" alors tu perds en puissance (force de Laplace F= I*B*L*sin(L,B) , tu dois connaitre )

sachant que ton champ magnetique de ton aimant est constant, a mon avis tu dois avoir B perpendiculaire a L (où passe I) pour avoir sin (L,B)=1 et donc une puissance max (t'as compris que L et B st des vecteurs)


A+

Louisnax

hello t'an qu'on parle de bobinage , le kv dépend t'il du nombre de tours et de l'épaisseur du fil?

Nonnon, pas con du tout!
The winding does not have to be nice and clean, magnetism and forces do not care. However, a neat and tidy winding job will leave more room for thicker wire.

About wire diameter:
First you have to figure/calculate the number of winds (tours) to get the Kv (rpm/Volt) you want.  For that number of winds, use the thickest wire possible (or wind 2-3 in parallel if one single wire would be too thick to handle comfortably). The thicker the wire(s) the lower the wire's resistance -> higher efficiency -> lower temperature,  longer flying and higher power/weight ratio (the motor can handle more Power_in)

Efficiency determines maximum power!

Wire thickness has no influence on Kv, unless the wire is too thin. Thin wire makes the rpm drop more under load.

Dernière modification par ron van sommeren (14/5/2008 23:20)

Higher efficiency does not only mean that the motor makes better use of the batteries' power, it also means the motor is able to handle a higher power input before hitting its maximum temperature mark i.e. a the power/weight ratio will be higher.
An example:
Say the motor has an efficiency of 70% and it can handle 50Watt input. That means it can get rid off 30%*50=15Watt excess heat. Now, by cramming in thicker wire (and/or using better stator-iron, segmented magnets), efficiency increases to say 75% (I'm a bit optimistic here). The motor's ability to loose those 15Watts has not changed (by radiation, convection and conduction). This means the motor now can handle 60Watt before it hits the 15Watt (25%*60Watt) losses mark. An efficiency increase of 5% gives an increase in the power to weight ratio of 20% (from 50Watt to 60Watt). That's why efficiency plays such an important role, in any motor design: efficiency governs maximum power. The motors weight may have increased a bit due to more copper.

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