SPS-Motor Analyse and first welcome

["dieter_wuertenberger" <dieter_wuertenberger@xxxxxxxxx>]

Hello David,

gratulation for Your FEMM-software. 

In the last weeks I did some optimization on very special DC-motors 
with FEMM. 
The type of motors I investigated are separated phase sector (SPS) 
machines, first published from:
THREE-PHASE LOW-SPEED PERMANENT MAGNET
SYNCHRONOUS MACHINES

P.Zielinski, K.Schoepp
Institute of Electrical Machine Systems
Technical University of Wroclaw
ul. Smoluchowskiego 19, 50-372 Wroclaw, Poland, 1991

and later on adapted for model pilot purpose by three german 
afficionados (... LRK-motors).

This motors have 6 coils and 7 permanent magnet polepairs. There 
speed of rotation is 7-times decreased re polepair=1 of standard 3-
phase motors, very optimal for low speed, high efficient airscrews in 
model airplanes. This motors are very popular today, supported with 
easy to assemble selfmade kits. 

The most used brush-motor cores in this kits are not optimal for SPS 
machines.
So I have developed with FEMM better core-geometries/magnet 
arrangements.
(see SPS_Motor.zip : LRK31_Mot2.fem with LRK1.lua/LRK1-post.lua )

After the static analyse I want to compute some harmonic effects. 
To do this I have some questions :

1. How can I model the windings (winding_classic.jpg) with "circuit" 
properties in FEMM to get eddy losses - mainly the loss of core ?

2. Is the eddy loss calculation in FEMM also accurate for my 
application ?
Block#1 (magnets+Fe-ring) rotate around block#0 ?
(--> rotating 3-phase field of stator delta-winding with superposed 
slightly oscillating field of rotating permanent magnets)



This to my questions for the moment, here some feedbacks to FEMMVIEW:

1. For static problem analysis it would be usefull to have B and J 
density together in one plot.

2. To have a optical clear and significant information of saturated 
areas with B>B_sat I have modified the color-table, so that we have 
from B=0 to B=B_ub-dta green/brown colors: For saturated areas we
have then pure red.
Unfortunately this feature is only available with postLUA ! 
We have to set B_lb=0 and B_ub=B_sat+(B_sat/11) in showdensityplot.
Color-Table:
<Color0> = 255	0	0
<Color1> = 215	74	7
<Color2> = 215	94	7
<Color3> = 215	114	7
<Color4> = 215	134	7
<Color5> = 215	154	7
<Color6> = 215	174	7
<Color7> = 215	194	7
<Color8> = 215	214	7
<Color9> = 215	234	7
<ColorA> = 215	254	7
<ColorB> = 255	255	255 

3. To select the output position/format of density plots for AVI-
outputs I have added the
config-parameters:
<WinLeft>	= 10	
<WinTop>	= 20
<WinWidth>	= 500	
<WinHeight>	= 483	
in femmview.cfg and femmwiew software. 

4. It would be informativ to have the "ProblemNote" Comment-String 
(one line) on top of all plots. 


Feedback to FEMM:
It would be usefull to have a instruction how to replace permanent 
magnets by coils for harmonic studies. 
(geometrie of coil arrangement/mesh-density/precision/current)

I found the best fitting parameters only by adaptiv variations.
See files HR383_Magnet.fem (static) <---> HR383_Coil.fem (harmonic)

Default: How is software feedback in the FEMM-group arranged ?


Upload-file : SPS_Motor.zip



Sincerely, D. Wuertenberger