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Products

C-core Manufacturing

I.General

II.Wound C-cores

III. Production tips

IV. Material properties & specifications

V.Design tips

I.General

ISOMATIC manufactures a range of C-cores (wound tape cores) for mains transformers to DIN 41309/IEC 329 specifications. You can see the main dimensions of these from the table below.

C-cores are wound from grain oriented silicon steel strips, annealed, impregnated and cut into two halves. They are very suitable for small mains transformers, exhibiting low noise, low magnetizing current, fast assembly of transformers, hence low cost of the final product.

Each pair is tested and marked for optimum performance.

C-cores, toroidal cores, epoxy coated toroidal cores and some types of stacked cores are manufactured with dimensions to customer specifications too.

II.Wound C-cores

Cores

The table contains the dimensions of the C-cores

which Isomatic can produce for you.

 

 

No
Type
Nr
P,VA
CORE DIMENSIONS
a
mm
b
mm
c
mm
h
mm
A
mm
H
mm
R
mm
Sfe
cm2
V
cm3
1
SLP 16x20
1
4,50
8 -0,36
20 +0,52
8
32
24,5 -0,7
49 -1,0
1~0,7
1,44
14,79
2
SLP 16x20
2
9
8 -0,36
20 +0,52
8
32
24,5 -0,7
49 -1,0
1~0,7
2,88
18,86
3
SLP 20x25
2
25
10 -0,36
25 +0,52
10
40
30,05 -0,7
61 -1,0
1~0,7
4,5
29,49
4
SLP 20x32
2
32
10 -0,58
32 +0,52
10
40
30,05 -0,7
61 -1,0
1~0,7
5,76
37,73
5
SL 20x25
2
68
10 -0,36
25 +0,52
20
50
40,5 -0,7
71 -1,4
1~0,7
4,5
37,62
6
SL 20x32-1,5
2
100
12,5 -0,58
32 +0,62
20
50
45,5 -0,7
76 -1,4
1~0,7
7,2
60,19
7
SL 20x50
2
130
10 -0,36
50 +0,62
20
50
40 -1,2
71 -1,4
1~0,7
9,3
99
8
SL 25x25
2
135
12,5 -0,43
25 +0,52
25
62,5
50,5 -0,7
89 -1,4
1~0,7
5,62
58,67
9
SL 36x45
2
250
17,5 -0,35
45 +0,52
18
53
53 -0,7
88 -0,7
1
14,64
167
10
SL 25x50
2
260
12,5 -0,7
50 +0,62
25
62,5
50,5 -1,2
89 -1,4
1~0,7
11,25
117,15
11
SL 25x75 *
*
390
12,5 -0,7
75 +0,82
25
62,5
50,5 -1,2
90 -1,4
1~0,7
16,87
175,72
12
SL 32x50
2
500
16 -0,7
50 +0,82
32
80
65 -1,4
114 -1,4
1~0,7
14,4
192,19
13
SL 80x40
1
*
40 -0,7
40 +0,7
80
110
170 -0,7
190 -1,4
2
14,88
864
14
PL 12,5x16-32
1
10
12,5 -0,43
16 +0,43
16
32
41,5 -0,7
58 -1,4
1~0,7
1,8
23,58
15
PL 16x20-32
1
18
16 -0,7
20 +0,62
16
32
48,5 -0,8
65 -1,4
1~0,7
2,97
52,8
16
PL 20x25-40
1
50
20 -0,7
25 +0,62
25
40
65,5 -1,2
80
1~0,7
4,5
106
17
PL 16x32-40
1
70
16 -0,7
32 +0,62
25
40
57,5 -1,2
73 -1,4
1~0,7
4,6
81,1
18
PL 16x32-62,5
1
100
16 -0,7
32 +0,62
25
62,5
57,5 -1,2
95 -1,4
1~0,7
4,6
94,61
19
PL 23x40-76
1
*
22,5
39,6(40)
31 +0,5
76 +0,5
76 -0,7

121 +0,75

1
8,37
282
20
PL 20x40-80
1
250
20 -0,84
40 +0,62
32
80
73
122
1~0,7
7,2
202,04
21
PL 20x40-80
2
500
20 -0,84
40 +0,62
32
80
73
122
1~0,7
14,4
202,04
22
PL 20x60-80**
*
750
20 -0,84
60 +0,62
32
80
73
122
1~0,7
21,6
303,07
23
PL 20x40-80
4
1000
20 -0,84
80 +0,62
32
80
73
122
1~0,7
28,8
404,09
24
PL 20x100-80***
*
1250
20 -0,84
100 +0,62
32
80
73
122
1~0,7
36
505,9
25
PL 20x40-80
5
1500
20 -0,84
120 +0,62
32
80
73
122
1~0,7
43,2
606,14
26
PL 20x140-80****
*
1750
20 -0,84
140 +0,62
32
80
73
122
1~0,7
50,4
707,2
27
PL 20x40-80
6
2000
20 -0,84
160 +0,62
32
80
73
122
1~0,7
57,6
808,19
28
PL 20x180-80*****
*
2250
20 -0,84
180 +0,62
32
80
73
122
1~0,7
64,8
909,2
29
PL 20x40-80
10
2500
20 -0,84
200 +0,62
32
80
73
122
1~0,7
72
1010,2
30
PL 22x40-80
1
*
22
40
32
80
77
126
1~0,7
7,92
285,6
31
PL 22,5x40-95
1
*
22,5
40
50
95
95
140
1~0,7
8,37
342
32
PL 32x40-80
1
*
32
40
32
80
97
146
1~0,7
11,9
464
33
PL 32x40-95
1
*
32
40
50
95
114
160
1
11,9
539,6
34
PL 32x40-97
1
*
32
40
32 -0,7
97
97
163
1~0,7
11,9
508,2
35
PL 32x40-123
1
*
32
40
51
123
115
190
1~0,7
11,9
623

Note  
* SL 25x25 - 2off + SL 25x50 - 2off
** PL 20x20 - 80 - 2off + PL 20x40 - 80 - 2off
*** PL 20x20 - 80 - 2off + PL 20x40 - 80 - 4off
**** PL 20x20 - 80 - 2off + PL 20x40 - 80 - 6off
***** PL 20x20 - 80 - 2off + PL 20x40 - 80 - 8off

III.Production tips

Isomatic operates a production line for C-cores and here the main stages are explained:

-Core winding
The strips are wound on special tools with the necessary core dimensions according to the standards and user’s specifications.

-Core annealing
To relieve the mechanical stresses after winding and improve the magnetic properties the cores are annealed. Annealing of the cores takes place in a tunnel furnace with a temperature 810 +10  oC. This allows precise control of the core’s mechanical dimensions and magnetic properties. The cores are then cooled in a pater noster

-Core impregnation
The cores are immersed in liquid enamel under vacuum and cured subsequently to become a single solid part.

-Core cutting
Cores are afterwards split into two halves on a special machine, using carefully selected cutting tools and coolant to obtain burr-free edges and low core losses.

IV. Material properties & specifications

We use cold rolled silicon steel. It has very high magnetic permeability at the direction of rolling which allows high values of the flux density within the core. Wound C-cores are very suitable for applications which require high flux densities because they provide small resistance for the magnetic flux along its way - the direction of the magnetic flux coincides with the direction of rolling. Thus a light and compact transformer can be designed.

V.Design tips
 

  • Flux Density in the core
     
    Bm = V/(4.44 f N S), [T]
     
    where:
    V- RMS value of the primary or secondary voltage [ V ]
    N - number of the primary or secondary turns
    f - Frequency
    S - cross section of the core
    Bm - maximum value of the flux density
     
  • Total no - load power
     
    S0=(P02+Q02)½
     
    where:
    P0 - no - load losses in [W]
    Q0 - excitation power, [VAR]
     
  • Core (no-load) losses
     
    P0 = p. GFE , [W]
     
    where :
    p - specific core losses , W/kg
    GFE - weight of the core, [kg]
     
  • Excitation power
    depends greatly on the material properties and the width of the air - gap
     
    Q0=qFE.GFE+nd. q0dSa , [VAR]
     
    qFE - specific excitation power of the core , [VA/kg]
    GFE - weight of the core, [kg]
    nd - the number of the air - gaps along the magnetic flux path q0d.
    Sa - specific excitation power of the air-gap , [VA/m2]
    q0d= pf.dCHBm2/m0 ,[VA/m]2
    dCH - the width of the air-gap
    dCH=0.005-0.3mm
    f - Frequency

    •  

    For more information or orders e-mail to isomatic@isomatic.com.
    Copyright © 2006 Isomatic Lab Ltd.