Linear Solenoid design
Linear Solenoid design
BOBIN DESIGN
Date: 26/11/8
Name : Raju Choppella.
Constraints as follows:
WIre Type: 42 SWG, Class-C
Dia: 0.1016 mm
R/L: 2.13Ω/meter.
Length: 46.9 meters (yielding 100 Ω)
Force: 13 N.
V: 12 VDC.
Number of turns:
No. of points of wire along H = H/(0.1016)
No. of points of wire along R = (R-2)/(0.1016)
So,
?n? number of turns = no of points along H * no of points along R.
?n? number of turns = H/(0.1016)* (R-2)/(0.1016)
So,
n = (H) * (R-2)/(0.1016)?
n = (H) * (R-2)*(92.875)-------(1)
We need to add some ?slippage? to counter any errors in the winding. How much? Say 10%?
Outer Radius and Height of the Bobin.
Volume of cylindrical ring = Volume of Wire taken.
π (R? - r?)* H = π*x?*l
So,
R? = √ ((x?*l/H)+r?)
As we know r = 2 mm
x = 0.1016/2 = 0.0508mm
l = 46.9m = 46900mm.
So,
R = √ ((0.0508)?*(46950)/H + (2)?)
R = √ ((121.16/H + (4))---------(2)
Force on a current carrying coil at the center of the coil.
For 1 turn;
B = μ * I / (2*R)
Where;
μ = 4π* 10 *
I = Current in the coil.
R = Radius of the coil.
Force(F) = n*I*L*B (for ?n? turns)-------(3)
Where;
n = number of turns.
I = Current.
L= Length of wire in meters.
B= magnetic Induction.
F = n*L*I*(μ * I / (2*R))
F = μ*L*n*I?/(2R)
Now F = 13 N.
F = (4π* 10 * )* (46.9)*n*I?/(2R)
So,
n*I? = F*2R/( μ*46.9)
n*I? = 13*2*R/(4π* 10 * )* (46.9)
n*I? = 441154.43*R------------(4)
Using equations 1, 2, 3 and 4 we have the following values for a range of bobin?s as below:
H(mm) R(mm) D(mm) n n*I? I? I(Amps)
5 5.313379 10.62676 1604.918117 2344.021 1.461 1.208718
6 4.918672 9.837344 1696.478046 2169.894 1.279 1.130929
7 4.616121 9.232242 1774.056931 2036.422 1.148 1.071448
8 4.3755 8.76 1841.012478 1930.271 1.048 1.023719
9 4.178782 8.36 1899.625892 1843.488 0.9095 0.953677
10 4.014474 8.02 1951.521507 1771.003 0.9704 0.985089
11 3.874861 7.74 1997.898435 1709.412 0.8556 0.924986
12 3.754553 7.5 2039.667621 1656.338 0.8121 0.901166
13 3.649658 7.299315 2077.537437 1610.063 0.775 0.880341
14 3.557286 7.114573 2112.069524 1569.313 0.743 0.861974
15 3.475246 6.950492 2143.716545 1533.12 0.7152 0.845695