Ferrofluid and its Effect on Distortions?

[brummkreisel]

Hi y'all,


I have a question about driver motors with FFL. Does FFL decrease the stray field by providing a closed magnetic loop? As a secondary effect, the field strength in the gap would increase (*), but more importantly, diminishing the stray field would decrease nonlinearities due to the stray field, e.g. eddies in the aluminum (aluminium) VC former, and possibly even affect BL linearities? Or wouldn't it? What do you think?

(Whether or not there is an overall gain in motor linearity (temperature-dependent viscosity of the FFL and nonlinear mechanical losses etc.), is another, yet also interesting question.)


Thanks & Cheers,
bk


(*) A search in the forum came up empty, although at one point someone quoted a third person stating that the field strenght increase would be marginally at best. One would have to discuss which field (B or H) does increase (if at all) and whether the respective field increase translates into higher efficiency.

[GM]

This subject gets a bit complex since you make a blend for the app. Here's an overview: http://www.ferrotec.com/usa/ferroflu...y_overview.htm

GM

[454Casull]

You'd have to take into account that ferrofluid is not completely ferromagnetic; ferrofluid (as indicated by the latter half of the name) requires a suspension to contain the ferrous particles.

[brummkreisel]

D'uh! Of course - the fluid will orient along the field lines rather than bend the field... thanks, Casull, my mistake, what was I thinking... I'm getting old, I guess...

GM, thanks for the interesting link!

Cheers from Montreal,
BK