MK Magnetics Core Specifications

Material Specifications for C-Cores & Uncased Toroids
Material Description
Material
Type Letter
Material
Thickness (inches
Space Factor
Watts/lb
VA/lb
B (kG)
Freq (Hz)
Gap VA per inch2
@ .001"
Gap VA per inch2
@ .002"
3% Silicon Steel Silectron®1
A
A&B
A
B&C
B
A
B&C
T
B&C
A
.001" 
.002" 
.004" 
.004" 
.007" 
.009" 
.009" 
.011" 
.011" 
.012" 
.83
.89
.90
.90
.92
.95
.95
.95
.95
.95
12.0 
10.0 
10.0 
15.0 
15.0 
0.89
0.89
0.89
0.89
0.89
20.3
15.0
13.1
39.5
39.5
1.7
1.5
1.7
1.5
1.7
12.5
15.0
15.0
17.6
17.6
15.0
17.6
15.0
17.6
15.0
400
400
400
400
400
60
60
60
60
60
16.3
29.2
29.9
41.1
43.0
5.0
6.9
5.0
6.9
5.0
32.6
58.4
58.8
82.2
86.0
10.0
13.8
10.0
13.8
10.0
80% Nickel-Iron Supermalloy®2
D
D
D
D
.0005"
.0010"
.0020"
.0040"
.65
.83
.89
.90
12.0 
14.0 
20.0 
15.0 
18.0
21.0
30.0
22.0
5.0
5.0
5.0
5.0
10,000
10,000
10,000
5,000
57.7
70.6
81.2
41.5
115.4
282.5
162.4
83.0
50% Nickel-Iron Deltamax®3
G
G
G
G
.0005"
.0010"
.0020"
.0040"
.65
.83
.89
.90
30.0 
37.0 
55.0 
3.5 
40.0
47.0
70.0
6.0
10.0
10.0
10.0
10.0
5000
5000
5000
400
115.3
141.2
162.4
13.0
230.6
282.5
324.8
26.0
50% Cobalt-Iron Supermendur®4  
J
J
.002" 
.004" 
.89
.90
18.0 
17.0 
65.0
60.0
20.0
21.0
400
400
52.0
58.6
104.0
117.2
Metglas®5 2605SA1
L
.001" 
.83
15.0 
N/A
2.0
20,000
18.5
36.9
Nanocrystalline
M
.0007"
.83
6.0 
N/A
2.0
20,000
18.5
36.9
kG is flux density in kilogauss. Watts/lb & VA/lb are reported power loss and excitation VA measured at the indicated flux (B) and frequency (Hz) with sine wave excitation. Gap VA for a 0.001" total air gap was calculated using the following formula: Gap VA = 4.1 x 10-4 x B² x frequency (Hz) x SF² x Ag . Cores under 25lbs use 0.001" air gap and those over 25lbs use 0.002" air gap. Total core watts = material watts/lb * core wgt. lbs. Total core excitation VA = material VA/lb * core wgt in lbs + gap VA.

Material Specifications for E-Cores
3% Silicon Steel Silectron®1
 A
B&C
B
B&C
A
T
B&C
.004"
.004"
.007"
.009"
.012"
.011"
.011"
.90
.90
.92
.95
.95
.95
.95
12.0
18.0
18.0
1.1
1.1
1.1
1.1
22.7
68.4
68.4
4.0
2.9
2.9
4.0
15.0
17.6
17.6
17.6
15.0
15.0
17.6
400
400
400
60
60
60
60
51.8
71.0
74.0
11.9
8.7
8.7
11.9
103.6
142.0
148.0
23.8
17.4
17.4
23.8
50% Cobalt-Iron Supermendur®4
 J
.004"
.90
20.0
108.0
21.0
400
58.6
101.0
Note: Total 3-phase core excitation VA = material VA/lb * core wgt in lbs + gap VA. VA for a total air gap of 0.0015" was calculated with the following formula: Gap VA = 6.15 x 10-4 x B² x frequency (Hz) x SF² x Ag . E-cores under 25 lbs use 0.0015" total air gap, E-cores over 25lbs use total air gap of 0.003". Total 3-phase core excitation VA = material VA/lb * core wgt in lbs + gap VA.
Note: 1. Silectron® is a registered trademark of Allegheny Ludlum Steel Corp. 2. Supermalloy® is the discontinued product name of Western Electric Co. 3. Deltamax® is the discontinued product name of Alleghney Ludlum Steel Corp. 4. Supermendur® is the discontinued product name of Carpenter Technology. 5. Metglas® is a registered trademark of Honeywell Metglas Solutions. 6. Finemet® is a registered trademark of Hitachi Metals Corp.