Magnet

Magnets have basic parameters and slots:

Parameter	Description	Default
mcvkey_yoke	Name of lamination material	dummy
mcvkey_shaft	Name of shaft material	dummy
material	Name of magnet material
nodedist	Factor for node distance	1.0

Note

• the mcvkey parameters either reference a filename without extension (Example ‘M330-50A’) which must be found in the directory defined by the parameter magnetizingCurves of the Femag constructor or the name of an entry in the Magnetizing Curve object.

• the material parameter references a name of the Magnet Material list.

magnetSector

Name		Unit	Comment
magn_num			number of magnets per pole
magn_height	HM	m
magn_width_pct			magnet width per pole width
magn_width	BM	m	used if magn_width_pct is undefined or 0
condshaft_r		m	conducting shaft radius
magn_rfe		m	inner radius of magnet
magn_len			relative magnet length
magn_shape		m
bridge_height	BH
bridge_width	BW
magn_ori			orientation 1: parallel, 2: polar, 3: halbach
magn_type			1: arc 2: arc par. 3: rect. 4: curved rect.

magn_type=1 (arc)

magn_type=2 (arc par)

magn_type=3 (rect)

magn_type=4 (curved rect)

magnetIron

Name		Unit	Comment
magn_height	HM	m
magn_width	BM	m
gap_ma_iron	DE_FEM	m
air_triangle	BS	m
iron_height	HS	m
magn_rem		T	magn. remanenc
condshaft_r		m	conducting shaft radius if < RI
magn_ori			orientation 1: parallel, 2: polar, 3: halbach
bridge_height	BH	m
bridge_width	BW	m
iron_shape	HA	m

magnetIron3

Name		Unit	Comment
magn_height	HM	m
magn_width	BM	m
gap_ma_iron	DE_FEM	m
air_triangle	BS	m
iron_height	HS	m
magn_num			number of magnets
condshaft_rad		m	conducting shaft radius if < RI
magn_ori			orientation 1: parallel, 2: polar, 3: halbach
gap_ma_right	BR	m
gap_ma_left	BL	m
iron_shape	HA	m

magnetIron4

Name		Unit	Comment
magn_height	HM	m
magn_width	BM	m
gap_ma_iron	DE_FEM	m
air_triangle	BS	m
iron_height	HS	m
air_space_h	H_air	m
corner_r	R1	m
magn_dist_ra	DM	m
air_sp_ori			orientation 0: lin 1: par RA
magn_ori			orientation 1: parallel, 2: polar, 3: halbach
magn_num			number of magnets (1 or 2)
iron_shape	HA	m

magnetIron5

Name		Unit	Comment
magn_height	HM	m
magn_width	BM	m
gap_ma_iron	DE_M	m
iron_bfe	BFE	m
iron_height	HS	m
air_space_h	H_air	m
air_space_b	B_air	m
corner_r	R1	m
magn_dist_ra	DM	m
air_sp_ori			orientation 0: lin 1: par RA
magn_num			number of magnets (1 or 2)
iron_shape	HA	m

magnetIronV

Name		Unit	Comment
magn_height	HM	m
magn_width	BM	m
magn_angle	ALPHA	Deg
gap_ma_iron	DE_M	m
iron_hs	HS	m
iron_height	BR	m
iron_shape	HA	m
air_triangle	BS	m
condshaft_r		m
magn_num			number of magnets

afm_rotor

Name		Unit	Comment
magn_height	hm	m
magn_width	wm		magnet width per pole width
yoke_height	hy	m

Name	Parameter
magnetIron2	magn_height, magn_width, gap_ma_iron, air_triangle, iron_height, magn_rem, condshaft_r, gap_ma_right, gap_ma_left, magn_ori, iron_shape
magnetFC2	yoke_height, iron_h1, iron_h2, iron_b, magn_width, magn_height, iron_bfe, iron_bfo, iron_shape, iron_hp, magn_num
<filename>	see User defined Magnet Slots with FSL
dxffile	see User defined Magnet Slots with DXF

Example:

machine = dict(
   name="PM 130 L4",
   lfe=0.1,
   poles=4,
   outer_diam=0.13,
   bore_diam=0.07,
   inner_diam=0.015,
   airgap=0.001,

   stator=dict(
       num_slots=12,
       num_slots_gen=3,
       mcvkey_yoke="dummy",
       rlength=1.0,
       stator1=dict(
           slot_rf1=0.057,
           tip_rh1=0.037,
           tip_rh2=0.037,
           tooth_width=0.009,
           slot_width=0.003)
       ),

   magnet=dict(
       mcvkey_shaft="dummy",
       mcvkey_yoke="dummy",
       magnetSector=dict (
           magn_num=1,
           magn_width_pct=0.8,
           magn_height=0.004,
           magn_shape=0.0,
           bridge_height=0.0,
           magn_type=1,
           condshaft_r=0.02,
           magn_ori=2,
           magn_rfe=0.0,
           bridge_width=0.0,
           magn_len=1.0 )
       ),

    windings=dict(
         num_phases=3,
         num_wires=100,
         coil_span=3.0,
         num_layers=1)
)

User defined Magnet Slots with FSL

Example

If a Mako or FSL file that creates the magnet geometry exists and is readable it can be used for the model creation as an empty dict (see Note in User defined Stator Slots with FSL):

machine = dict(
    name="Motor",
    ...
    magnet=dict(
        mcvkey_yoke='dummy',
        mcvkey_shaft="dummy",
        myrotor=dict()
    ),
    ...

User defined Magnet Slots with DXF

If a DXF file that defines the magnet geometry exists and is readable it can be used to create the FSL for the model.

Example:

machine = dict(
    name="Motor",
    ...
    magnet=dict(
        mcvkey_yoke='dummy',
        mcvkey_shaft="dummy",
        dxffile=dict(
            name='mymagnet.dxf',
            position='in',
            split=True
        )
    ),
    ...

Parameters	Description	Default
position	‘in’ or ‘out’
split	splits intersecting lines at their intersection points	False
plot	creates the plot of the integrated object	False

Note

The split option is required only if intersecting lines have no common point.

User Specified Magnet Geometries

Magnet geometries not covered by the built in models can be specified by fsl code. Here is a example:

Example of a user specified geometry (created with TikZ)

The steps are:

1. Create a diagram of the geometry and decide about the parameters to be used.

2. Create a fsl mako template file with the chosen parameters as placeholders using the Mako syntax with ${}.

3. Include this filename in the magnet model within the section using the basename of the mako file and set the parameter values.

The following values are defined globally and can be referenced in the template:

Name	Description	Unit
mcvkey_yoke	lamination material of yoke
mcvkey_shaft	material of shaft
m.remanenc	Remanence Induction	T
m.relperm	Rel. Permeability of PM
m.num_poles	Number of poles
m.npols_gen	Number of poles in model
agndst	Node distance in airgap	m
dy1	Diameter of stator yoke	m
da1	Diameter of stator bore	m
da2	Diameter of rotor	m
dy2	Diameter of rotor yoke	m

Example FSL Template file ‘’spoke.mako’’ using 4 parameters:

-- Model parameters

ds = ${model['shaft_diam']}*1e3
hm = ${model['magn_height']}*1e3
bm = ${model['magn_width']}*1e3
ws = ${model['slot_width']}*1e3

-- calculate slot height and pole pitch
hs = (da2-dy2)/2 - bm
taup = math.pi/m.num_poles

x = {}
y = {}

-- characteristic points of model

ar = math.sqrt(dy2^2+hm^2)/2
x[1] = ar*math.cos(taup - math.atan2(hm/2, dy2/2))
y[1] = 0
x[2],y[2] = pr2c(dy2/2+bm, 0)
x[3],y[3] = pr2c(da2/2, 0)
x[4],y[4] = pr2c(da2/2, taup - math.atan2(ws/2,(da2/2)))
x[5],y[5] = pr2c(da2/2-hs, taup - math.atan2(ws/2,(da2/2 - hs)))
x[6],y[6] = pr2c(da2/2-hs, taup - math.atan2(hm/2, da2/2-hs))
x[7],y[7] = pr2c(ar, taup - math.atan2(hm/2, dy2/2))
x[8],y[8] = pr2c(dy2/2, taup)
x[9],y[9] = pr2c(da2/2 - hs, taup)
x[10],y[10] = pr2c(da2/2, taup)

Magnet definition in Python file with included mako file (eg in this case ‘’spoke’’) and the parameter definition:

..
magnet=dict(
    mcvkey_yoke="dummy",
    spoke=dict(
        magn_height=0.008,
        shaft_diam=0.01,
        slot_width=0.004,
        magn_width=0.024
    )
 ..

The resulting model:

Note

Starting with Release 0.4.4 the syntax has changed but backward compatibility is fully supported.

the complete example can be found in stator1-spoke.py and spokefml.mako in the example directory on github.