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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