MIL-HDBK-1004/10
d) Number of anodes required. Anode size of 1-1/2 inches in
diameter by 9 inches long weighing 4 pounds each is selected as the most
suitable size. In order to get proper current distribution, three anodes are
required.
e)
Resistance of single anode:
R=
0.012P log (D/d)/L
where
P
=
8,600 ohm-cm
D
=
3.83 feet, tank diameter
d
=
1-1/2 inches or 0.125 foot, anode diameter
L
=
9 inches or 0.75 foot, anode length
R
=
0.012 x 8,600 log (3.83/0.125)/0.75
R
=
103.2 x log 30.64/0.75
R
=
103.2 x 1.486/0.75
R
=
204.5 ohms
This resistance must be corrected by the fringe factor because they
are short anodes. The fringe factor is 0.48 from the curve in Figure 101 for
an L/d = 9/1.5 = 6:
R = 204.5 x 0.48
R = 98.2 ohms
f)
Resistance of 3 anode group:
R
= (1n)R
+ (Pxp)/S
n
v
where
R
= total anode-to-electrolyte resistance
n
n = number of anodes
R = resistance-to-electrolyte of a single anode
v
P = electrolyte resistivity
p = "paralleling factor" (from para. 6.2.1.4b)
S = spacing between anodes (feet)
R
= 1/3(98.2) + (8,600 x 0.00289/4)
n
R
= 38.94 ohms
n
g)
Rectifier rating:
(1)
E = IR
189
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