Magnetic Autocontrol MAGSTOP MBE35, Operating Instructions Manual, Page: 46 / 58

Operation Instructions
MBE35_50 OPERATION MANUAL 2005_10
46
5.2.4 Loop Inductance calculations
The number of turns required in the loop is dependent on the loop size. The loop
inductance can be calculated as follows:
L = P/4 (t² +t)
L = Inductance (micro Henries)
P = Perimeter (feet)
t = Number of turns
The formula can be simplified to: L = PK
Substituting a constant K for (t² +t)/4
Filling in the Number of Turns and calculating K:
Note:
Use the highlighted values to determine the number of turns required. ALWAYS USE
AT LEAST 2 TURNS. In addition to the above result, the inductivity of the wires used
in the loop must be added. Depending on the used wire, it is between 1 – 1.5
µ
H per
every three (3) feet.
Example: 4’ x 8’ with 4 turns
L = PK
P = 4’+4’+8’+8’= 24 feet
K = 5.0
L = 24 x 5.0
L = 120 micro henries
Number Of Turns
(t) k (constant)
k= (t2 + t)/4
2 1.5
3 3
4 5
5 7.5
6 11.5
7 14
NUMBER OF TURNS
2 3 4 5 6 7
10 15 30 50 75 115 140
20 30 60 100 150 230 280
30 45 90 150 225 345 420
40
60 120 200 300 460 560
50 75 150 250 275 575 700
60 90 180 300 450 690 840
70 105 210 350 525 805 980
80 120 240 400 600 920 1120
90 135 270 450 675 1035 1260
PER
IMETER FEET
100
150 300 500 750 1150 1400
☞